diff --git a/.gitignore b/.gitignore
index ce1af70..520411d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -38,3 +38,5 @@ clients/rust/target/
 clients/nim/src/baradb/client
 src/barabadb/storage/compaction
 docker-compose.test.yml
+src/barabadb/query/executor
+tests/join_tests
diff --git a/PLAN_SQL_ADVANCED.md b/PLAN_SQL_ADVANCED.md
index cd6c0b3..0e2fcbe 100644
--- a/PLAN_SQL_ADVANCED.md
+++ b/PLAN_SQL_ADVANCED.md
@@ -3,6 +3,8 @@
 > **Визия**: BaraDB е самостоятелен, универсален SQL engine с Nim ядро, поддържащ модерни SQL:2023 разширения — Property Graph, Vector Search, JSON документи и прозоречни функции, в една вградена или клиент/сървър конфигурация.
 > 
 > **Принцип**: Само основи. Не се добавят нови светове — само стабилизираме и документираме съществуващите.
+>
+> **Multi-Tenant фокус**: BaraDB е проектирана да поддържа ERP сценарии с много фирми (tenants) в една база данни. Всеки tenant се изолира чрез Row-Level Security (RLS) + session variables (`SET app.tenant_id = 'X'`), а не чрез отделни бази.
 
 ---
 
@@ -10,7 +12,7 @@
 
 - **Фаза 1 (Base SQL + MVCC + Raft)**: BaraDB core engine
 - **Фаза 2 (Advanced SQL)**: Разработена с **Xiaomi Mimo** (`mimo-v2.5-pro`) — Window Functions, MERGE, LATERAL JOIN, Advanced Aggregates, PIVOT/UNPIVOT, SQL/PGQ Property Graph
-- **Фаза 3 (Stabilization)**: Текуща — Vector SQL Integration, тестове, документация
+- **Фаза 3 (Stabilization + Multi-Tenant)**: Текуща — Vector SQL Integration, Session Variables, `current_user`/`current_role`, RLS tenant isolation, тестове, документация
 
 ---
 
@@ -167,6 +169,49 @@ SELECT * FROM GRAPH_TABLE(org_chart
 
 ---
 
+## Част 1.5: Multi-Tenant ERP Support ✅ ГОТОВО
+
+BaraDB поддържа multi-tenant архитектура, при която множество фирми (tenants) работят в една физическа база данни. Това е критично за ERP сценарии, където поддръжката на "сто бази" не е опция.
+
+### Механизъм
+
+| Компонент | Описание |
+|-----------|----------|
+| **Session Variables** | `SET app.tenant_id = 'company-123'` — задава tenant за текущата сесия |
+| **current_setting()** | `current_setting('app.tenant_id')` — чете session променлива в SQL израз |
+| **current_user** | `current_user` — връща автентикирания потребител от JWT/SCRAM |
+| **current_role** | `current_role` — връща ролята на автентикирания потребител |
+| **RLS Policies** | `CREATE POLICY tenant_isolation ON invoices FOR SELECT USING (tenant_id = current_setting('app.tenant_id'))` |
+| **Auth Bridge** | `server.nim` и `httpserver.nim` попълват `ExecutionContext.currentUser`/`currentRole` след верификация |
+
+### Пример
+
+```sql
+-- Една таблица за всички фирми
+CREATE TABLE invoices (
+  id SERIAL PRIMARY KEY,
+  tenant_id TEXT NOT NULL,
+  data JSONB
+);
+
+-- Изолация чрез RLS
+CREATE POLICY tenant_isolation ON invoices
+  FOR SELECT USING (tenant_id = current_setting('app.tenant_id'));
+
+-- Всяка сесия вижда само своя tenant
+SET app.tenant_id = 'company-a';
+SELECT * FROM invoices;  -- → само фактури на company-a
+```
+
+### Архитектурни предимства
+
+- **JSONB документи** — schema-flexible, лесно се добавят нови полета без миграции (като ArangoDB)
+- **RLS изолация** — базата данни гарантира, че всеки tenant вижда само своите данни
+- **Един instance** — един BaraDB сървър обслужва всички tenants, вместо сто отделни бази
+- **Auth integration** — JWT/SCRAM токените носят `sub` (user) и `role`, които се пропагират до executor-а
+
+---
+
 ## Част 2: Мултимодални Възможности (Core Only)
 
 ### 2.1 JSON / JSONB Документи ✅ ГОТОВО
@@ -290,6 +335,16 @@ LIMIT 10;
 - **MERGE тестове** — поправени чрез изолиране на тестовата директория (unique temp dir per suite)
 - **Row storage escape** — `escapeRowVal()` в `execInsert` за стойности със запетай (vector literals)
 - **ORDER BY + projection** — `irpkSort` сега е преди `irpkProject` в `lowerSelect`, което позволява `ORDER BY` по колони извън `SELECT`
+- **GROUPING SETS execution** — `lowerSelect` сега проверява `selGroupingSetsKind != gskNone` освен `selGroupBy.len > 0`, което позволява изпълнение на GROUPING SETS без традиционен GROUP BY
+- **FTS CREATE INDEX docId** — поправено несъответствие в изчислението на `docId` при `CREATE INDEX ... USING FTS` (сега използва хеш на `tableName.$key`, съвместим с DML операциите)
+- **Тестова изолация (всички suite-ове)** — всички `newLSMTree("")` заменени с уникални temp директории; setup/teardown за suite-ове с изолирана state
+- **Multi-tenant ERP support** — имплементирани критични градивни елементи:
+  - `SET var = value` — session variables за tenant isolation
+  - `current_setting('var')` — четене на session променливи в SQL изрази
+  - `current_user` / `current_role` — SQL keywords, които се оценяват от `ExecutionContext`
+  - Auth bridge — `server.nim` и `httpserver.nim` попълват `currentUser`/`currentRole` след JWT/SCRAM верификация
+  - RLS tenant isolation тест — `CREATE POLICY` + `current_setting('app.tenant_id')` работи за multi-tenant филтрация
+  - `evalExpr` вече предава `ctx` рекурсивно — поправен бъг, при който `current_user`/`current_setting` връщаха празни стойности в под-изрази
 
 ---
 
diff --git a/docs/en/baraql.md b/docs/en/baraql.md
index f4b9061..33920ae 100644
--- a/docs/en/baraql.md
+++ b/docs/en/baraql.md
@@ -602,6 +602,44 @@ SUM(salary) OVER (
 )
 ```
 
+## Multi-Tenant ERP
+
+BaraDB supports running multiple companies (tenants) in a single database instance, using **Row-Level Security (RLS)** combined with **session variables**.
+
+### Session Variables
+
+```sql
+SET app.tenant_id = 'company-123';
+SELECT current_setting('app.tenant_id') AS tenant;
+```
+
+### Current User / Role
+
+```sql
+SELECT current_user AS me, current_role AS my_role;
+```
+
+### RLS Tenant Isolation
+
+```sql
+-- Enable RLS on a table
+ALTER TABLE invoices ENABLE ROW LEVEL SECURITY;
+
+-- Create a policy that filters by tenant
+CREATE POLICY tenant_isolation ON invoices
+  FOR SELECT USING (tenant_id = current_setting('app.tenant_id'));
+
+-- Each session only sees its own data
+SET app.tenant_id = 'company-a';
+SELECT * FROM invoices;  -- only company-a rows
+```
+
+### Why Multi-Tenant?
+
+- **One instance, many tenants** — no need to run 100 separate databases
+- **JSONB documents** — schema-flexible storage, easy to add fields per tenant
+- **RLS guarantees isolation** — the database enforces tenant boundaries, not just the application
+
 ## Supported Keywords
 
 | Category | Keywords |
@@ -620,6 +658,7 @@ SUM(salary) OVER (
 | JSON | ->, ->> |
 | FTS | @@ (BM25 match) |
 | Recovery | RECOVER TO TIMESTAMP |
-| Functions | count, sum, avg, min, max, stddev, variance, abs, sqrt, lower, upper, len, trim, substr, now, last_insert_id |
+| Functions | count, sum, avg, min, max, stddev, variance, abs, sqrt, lower, upper, len, trim, substr, now, last_insert_id, current_setting |
+| Session | SET, current_setting, current_user, current_role |
 | Window | OVER, PARTITION BY, ROWS, RANGE, UNBOUNDED PRECEDING, CURRENT ROW, FOLLOWING |
 | Window Functions | ROW_NUMBER, RANK, DENSE_RANK, LEAD, LAG, FIRST_VALUE, LAST_VALUE, NTILE |
diff --git a/docs/en/changelog.md b/docs/en/changelog.md
index 9356412..41d6209 100644
--- a/docs/en/changelog.md
+++ b/docs/en/changelog.md
@@ -2,6 +2,26 @@
 
 All notable changes to BaraDB are documented in this file.
 
+## [Unreleased] — SQL:2023 Stabilization
+
+### Fixed
+
+- **GROUPING SETS execution** — `lowerSelect` now creates `irpkGroupBy` when `selGroupingSetsKind != gskNone`, even if `selGroupBy` is empty. Previously, queries like `GROUP BY GROUPING SETS ((dept), ())` bypassed the grouping executor entirely.
+- **FTS CREATE INDEX docId mismatch** — `CREATE INDEX ... USING FTS` now computes `docId` as a hash of `tableName.$key`, consistent with DML operations (`INSERT`/`UPDATE`/`DELETE`). Previously, index creation used sequential IDs (0, 1, 2...), causing `@@` queries to never match indexed documents.
+- **Test isolation (all suites)** — All `newLSMTree("")` calls replaced with unique temporary directories per suite. Eliminates WAL accumulation issues and flaky tests caused by shared database state between test runs.
+- **Window frame parser** — `parseFrameBoundary` no longer consumes `tkRow` after `tkCurrent` incorrectly (was using `tkRows`). Also fixed `tkRow` keyword conflict with `ENABLE ROW LEVEL SECURITY` parsing.
+- **ORDER BY + SELECT projection** — `lowerSelect` now places `irpkSort` before `irpkProject`, enabling `ORDER BY` on columns not present in the `SELECT` list.
+- **UNPIVOT execution** — Verified and fixed missing test coverage for UNPIVOT transformation.
+
+### Added
+
+- **JSON operators** — `@>` (contains), `<@` (contained by), `?` (has key), `?|` (has any), `?&` (has all) now supported in lexer, parser, and executor.
+- **Window frame execution** — `ROWS BETWEEN X PRECEDING AND Y FOLLOWING` / `CURRENT ROW` frame boundaries now respected by `FIRST_VALUE` and `LAST_VALUE`.
+- **Session variables** — `SET var_name = value` and `current_setting('var_name')` for connection-scoped key/value storage.
+- **Current user/role** — `current_user` and `current_role` SQL keywords evaluate to the authenticated session's user and role.
+- **Auth-executor bridge** — Wire server and HTTP server now populate `ExecutionContext.currentUser` and `ExecutionContext.currentRole` after JWT/SCRAM authentication.
+- **Multi-tenant RLS** — Row-Level Security policies can now reference `current_user`, `current_role`, and `current_setting('app.tenant_id')` for per-tenant data isolation.
+
 ## [1.1.0] — 2026-05-13
 
 ### Added
diff --git a/src/barabadb/core/httpserver.nim b/src/barabadb/core/httpserver.nim
index 9f89e56..1d5b4d3 100644
--- a/src/barabadb/core/httpserver.nim
+++ b/src/barabadb/core/httpserver.nim
@@ -108,6 +108,8 @@ proc queryHandler(server: HttpServer): RequestHandler =
       let ctx = newContext(request)
       server.metrics.queriesTotal += 1
 
+      var userId = ""
+      var role = ""
       # Auth check
       if server.config.authEnabled:
         let authHeader = request.headers["Authorization"]
@@ -115,10 +117,12 @@ proc queryHandler(server: HttpServer): RequestHandler =
           ctx.json(%*{"error": "Unauthorized"}, 401)
           return
         let tokenStr = authHeader[7..^1]
-        let (valid, userId, role) = server.verifyToken(tokenStr)
+        let (valid, uid, r) = server.verifyToken(tokenStr)
         if not valid:
           ctx.json(%*{"error": "Unauthorized"}, 401)
           return
+        userId = uid
+        role = r
 
       let body = parseJson(request.body)
       if body == nil or "query" notin body:
@@ -131,6 +135,8 @@ proc queryHandler(server: HttpServer): RequestHandler =
         return
 
       var reqCtx = cloneForConnection(server.ctx)
+      reqCtx.currentUser = userId
+      reqCtx.currentRole = role
       let tokens = tokenize(queryStr)
       let astNode = parse(tokens)
 
diff --git a/src/barabadb/core/server.nim b/src/barabadb/core/server.nim
index 7ae8bb5..55647d9 100644
--- a/src/barabadb/core/server.nim
+++ b/src/barabadb/core/server.nim
@@ -436,9 +436,11 @@ proc handleClient(server: Server, client: AsyncSocket, clientId: int) {.async.}
       case header.kind
       of mkAuth:
         let tokenStr = parseAuthMessage(cast[seq[byte]](payload))
-        let (valid, userId, _) = verifyToken(secret, tokenStr)
+        let (valid, userId, role) = verifyToken(secret, tokenStr)
         if valid:
           authenticated = true
+          connCtx.currentUser = userId
+          connCtx.currentRole = role
           let okMsg = makeAuthOkMessage(header.requestId)
           await client.send(cast[string](okMsg))
           info("Client " & $clientId & " authenticated as " & userId)
diff --git a/src/barabadb/query/ast.nim b/src/barabadb/query/ast.nim
index b600409..e4b9609 100644
--- a/src/barabadb/query/ast.nim
+++ b/src/barabadb/query/ast.nim
@@ -40,6 +40,7 @@ type
     nkDisableRLS
     nkGrant
     nkRevoke
+    nkSetVar
 
     # Clauses
     nkFrom
@@ -78,6 +79,8 @@ type
     nkIsExpr
     nkStar
     nkPlaceholder
+    nkCurrentUser
+    nkCurrentRole
 
     # Graph-specific
     nkGraphTraversal
@@ -144,6 +147,10 @@ type
     bkJsonPathText = "->>"
     bkFtsMatch = "@@"
     bkDistance = "<->"
+    bkJsonContains = "@>"
+    bkJsonContainedBy = "<@"
+    bkJsonHasAny = "?|"
+    bkJsonHasAll = "?&"
 
   UnaryOpKind* = enum
     ukNeg = "-"
@@ -317,6 +324,9 @@ type
       rvPrivilege*: string
       rvTable*: string
       rvGrantee*: string
+    of nkSetVar:
+      svName*: string
+      svValue*: string
     of nkApplyMigration:
       amName*: string
     of nkMigrationStatus:
@@ -484,6 +494,10 @@ type
       discard
     of nkPlaceholder:
       discard
+    of nkCurrentUser:
+      discard
+    of nkCurrentRole:
+      discard
     of nkPropertyDef:
       pdName*: string
       pdType*: string
diff --git a/src/barabadb/query/executor b/src/barabadb/query/executor
deleted file mode 100755
index 65e04c0..0000000
Binary files a/src/barabadb/query/executor and /dev/null differ
diff --git a/src/barabadb/query/executor.nim b/src/barabadb/query/executor.nim
index 5ac4022..db69967 100644
--- a/src/barabadb/query/executor.nim
+++ b/src/barabadb/query/executor.nim
@@ -69,6 +69,7 @@ type
     policies*: Table[string, seq[PolicyDef]]  # table name -> policies
     currentUser*: string
     currentRole*: string
+    sessionVars*: Table[string, string]  # session-scoped key/value variables
 
   MigrationRecord* = object
     name*: string
@@ -149,6 +150,7 @@ proc newExecutionContext*(db: LSMTree): ExecutionContext =
                    users: initTable[string, UserDef](),
                    policies: initTable[string, seq[PolicyDef]](),
                    currentUser: "", currentRole: "",
+                   sessionVars: initTable[string, string](),
                    onChange: nil)
   restoreSchema(result)
 
@@ -323,6 +325,7 @@ proc cloneForConnection*(ctx: ExecutionContext): ExecutionContext =
                    users: ctx.users, policies: ctx.policies,
                    txnManager: ctx.txnManager,
                    currentUser: ctx.currentUser, currentRole: ctx.currentRole,
+                   sessionVars: ctx.sessionVars,
                    pendingTxn: nil, onChange: ctx.onChange)
 
 # ----------------------------------------------------------------------
@@ -504,7 +507,7 @@ proc evalExpr*(expr: IRExpr, row: Table[string, string], ctx: ExecutionContext =
   of irekStar:
     return "*"
   of irekJsonPath:
-    let srcVal = evalExpr(expr.jpExpr, row)
+    let srcVal = evalExpr(expr.jpExpr, row, ctx)
     if srcVal.len == 0: return ""
     try:
       let node = parseJson(srcVal)
@@ -527,8 +530,8 @@ proc evalExpr*(expr: IRExpr, row: Table[string, string], ctx: ExecutionContext =
     except:
       return ""
   of irekBinary:
-    let left = evalExpr(expr.binLeft, row)
-    let right = evalExpr(expr.binRight, row)
+    let left = evalExpr(expr.binLeft, row, ctx)
+    let right = evalExpr(expr.binRight, row, ctx)
     case expr.binOp
     of irEq:
       if left == right: return "true"
@@ -669,20 +672,93 @@ proc evalExpr*(expr: IRExpr, row: Table[string, string], ctx: ExecutionContext =
       if vecA.len == 0 or vecB.len == 0:
         return "0"
       return $vengine.euclideanDistance(vecA, vecB)
+    of irJsonContains:
+      # Check if left JSON contains right JSON
+      try:
+        let leftNode = parseJson(left)
+        let rightNode = parseJson(right)
+        if leftNode.kind == JObject and rightNode.kind == JObject:
+          for key, val in rightNode:
+            if not leftNode.hasKey(key) or $(leftNode[key]) != $val:
+              return "false"
+          return "true"
+        elif leftNode.kind == JArray and rightNode.kind == JArray:
+          for ritem in rightNode:
+            var found = false
+            for litem in leftNode:
+              if $(litem) == $(ritem):
+                found = true
+                break
+            if not found:
+              return "false"
+          return "true"
+        else:
+          return if $(leftNode) == $(rightNode): "true" else: "false"
+      except:
+        return "false"
+    of irJsonContainedBy:
+      # Check if left JSON is contained by right JSON (reverse of contains)
+      try:
+        let leftNode = parseJson(left)
+        let rightNode = parseJson(right)
+        if leftNode.kind == JObject and rightNode.kind == JObject:
+          for key, val in leftNode:
+            if not rightNode.hasKey(key) or $(rightNode[key]) != $val:
+              return "false"
+          return "true"
+        elif leftNode.kind == JArray and rightNode.kind == JArray:
+          for litem in leftNode:
+            var found = false
+            for ritem in rightNode:
+              if $(ritem) == $(litem):
+                found = true
+                break
+            if not found:
+              return "false"
+          return "true"
+        else:
+          return if $(leftNode) == $(rightNode): "true" else: "false"
+      except:
+        return "false"
+    of irJsonHasAny:
+      # Check if JSON object has any of the keys in right array
+      try:
+        let leftNode = parseJson(left)
+        let rightNode = parseJson(right)
+        if leftNode.kind == JObject and rightNode.kind == JArray:
+          for key in rightNode:
+            if key.kind == JString and leftNode.hasKey(key.getStr()):
+              return "true"
+        return "false"
+      except:
+        return "false"
+    of irJsonHasAll:
+      # Check if JSON object has all of the keys in right array
+      try:
+        let leftNode = parseJson(left)
+        let rightNode = parseJson(right)
+        if leftNode.kind == JObject and rightNode.kind == JArray:
+          for key in rightNode:
+            if key.kind == JString and not leftNode.hasKey(key.getStr()):
+              return "false"
+          return "true"
+        return "false"
+      except:
+        return "false"
     else: return "false"
   of irekUnary:
     case expr.unOp
     of irNot:
-      let v = evalExpr(expr.unExpr, row)
+      let v = evalExpr(expr.unExpr, row, ctx)
       return if v == "true": "false" else: "true"
     of irIsNull:
-      let v = evalExpr(expr.unExpr, row)
+      let v = evalExpr(expr.unExpr, row, ctx)
       return if isNull(v): "true" else: "false"
     of irIsNotNull:
-      let v = evalExpr(expr.unExpr, row)
+      let v = evalExpr(expr.unExpr, row, ctx)
       return if not isNull(v): "true" else: "false"
     of irNeg:
-      let v = evalExpr(expr.unExpr, row)
+      let v = evalExpr(expr.unExpr, row, ctx)
       try:
         let f = -parseFloat(v)
         let s = $f
@@ -716,6 +792,37 @@ proc evalExpr*(expr: IRExpr, row: Table[string, string], ctx: ExecutionContext =
         return "0"
       let arg = evalExpr(expr.irFuncArgs[0], row, ctx)
       return $parseVectorString(arg).len
+    of "json_has_key":
+      if expr.irFuncArgs.len < 2:
+        return "false"
+      let jsonStr = evalExpr(expr.irFuncArgs[0], row, ctx)
+      let key = evalExpr(expr.irFuncArgs[1], row, ctx)
+      try:
+        let node = parseJson(jsonStr)
+        if node.kind == JObject:
+          return if node.hasKey(key): "true" else: "false"
+        elif node.kind == JArray:
+          try:
+            let idx = parseInt(key)
+            return if idx >= 0 and idx < node.len: "true" else: "false"
+          except:
+            return "false"
+        return "false"
+      except:
+        return "false"
+    of "current_setting":
+      if expr.irFuncArgs.len < 1:
+        return ""
+      let key = evalExpr(expr.irFuncArgs[0], row, ctx)
+      if ctx != nil and key in ctx.sessionVars:
+        return ctx.sessionVars[key]
+      return ""
+    of "current_user":
+      if ctx != nil: return ctx.currentUser
+      return ""
+    of "current_role":
+      if ctx != nil: return ctx.currentRole
+      return ""
     else:
       # Unknown function: try to evaluate args and return first arg as fallback
       if expr.irFuncArgs.len > 0:
@@ -773,7 +880,7 @@ proc passesPolicy(ctx: ExecutionContext, tableName, command: string, row: Row):
       continue
     if pol.usingExpr != nil:
       let expr = lowerExpr(pol.usingExpr)
-      if evalExpr(expr, row) != "true":
+      if evalExpr(expr, row, ctx) != "true":
         return false
   return true
 
@@ -788,7 +895,7 @@ proc checkInsertPolicy(ctx: ExecutionContext, tableName: string, row: Row): bool
       continue
     if pol.withCheckExpr != nil:
       let expr = lowerExpr(pol.withCheckExpr)
-      if evalExpr(expr, row) != "true":
+      if evalExpr(expr, row, ctx) != "true":
         return false
   return true
 
@@ -1151,7 +1258,7 @@ proc validateConstraints*(ctx: ExecutionContext, tableName: string,
           else:
             row[f] = ""
         let checkExpr = lowerExpr(check.checkNode)
-        let checkResult = evalExpr(checkExpr, row)
+        let checkResult = evalExpr(checkExpr, row, ctx)
         if checkResult != "true":
           return (false, "CHECK constraint '" & check.name & "' violated")
 
@@ -1199,6 +1306,14 @@ proc lowerExpr*(node: Node): IRExpr =
   of nkNullLit:
     result = IRExpr(kind: irekLiteral)
     result.literal = IRLiteral(kind: vkNull)
+  of nkCurrentUser:
+    result = IRExpr(kind: irekFuncCall)
+    result.irFunc = "current_user"
+    result.irFuncArgs = @[]
+  of nkCurrentRole:
+    result = IRExpr(kind: irekFuncCall)
+    result.irFunc = "current_role"
+    result.irFuncArgs = @[]
   of nkIdent:
     result = IRExpr(kind: irekField)
     result.fieldPath = @[node.identName]
@@ -1229,6 +1344,10 @@ proc lowerExpr*(node: Node): IRExpr =
     of bkOr: irOp = irOr
     of bkFtsMatch: irOp = irFtsMatch
     of bkDistance: irOp = irDistance
+    of bkJsonContains: irOp = irJsonContains
+    of bkJsonContainedBy: irOp = irJsonContainedBy
+    of bkJsonHasAny: irOp = irJsonHasAny
+    of bkJsonHasAll: irOp = irJsonHasAll
     else: irOp = irEq
     result.binOp = irOp
     result.binLeft = lowerExpr(node.binLeft)
@@ -1408,7 +1527,7 @@ proc lowerSelect*(node: Node): IRPlan =
     filterPlan.filterCond = lowerExpr(node.selWhere.whereExpr)
     result = filterPlan
 
-  if node.selGroupBy.len > 0:
+  if node.selGroupBy.len > 0 or node.selGroupingSetsKind != gskNone:
     let groupPlan = IRPlan(kind: irpkGroupBy)
     groupPlan.groupSource = result
     groupPlan.groupKeys = @[]
@@ -1477,17 +1596,17 @@ proc lowerSelect*(node: Node): IRPlan =
 # Window Function Computation
 # ----------------------------------------------------------------------
 
-proc partitionKey(row: Row, partExprs: seq[IRExpr]): string =
+proc partitionKey(row: Row, partExprs: seq[IRExpr], ctx: ExecutionContext = nil): string =
   ## Compute a string partition key for a row
   result = ""
   for expr in partExprs:
-    result &= evalExpr(expr, row) & "|"
+    result &= evalExpr(expr, row, ctx) & "|"
 
-proc compareRowsByOrder(a, b: Row, orderExprs: seq[IRExpr], orderDirs: seq[bool]): int =
+proc compareRowsByOrder(a, b: Row, orderExprs: seq[IRExpr], orderDirs: seq[bool], ctx: ExecutionContext = nil): int =
   ## Compare two rows by their ORDER BY expressions
   for i, expr in orderExprs:
-    let va = evalExpr(expr, a)
-    let vb = evalExpr(expr, b)
+    let va = evalExpr(expr, a, ctx)
+    let vb = evalExpr(expr, b, ctx)
     var cmpRes = 0
     try:
       let fa = parseFloat(va)
@@ -1500,18 +1619,63 @@ proc compareRowsByOrder(a, b: Row, orderExprs: seq[IRExpr], orderDirs: seq[bool]
       return if orderDirs.len > i and orderDirs[i]: -cmpRes else: cmpRes
   return 0
 
-proc computeWindowValues*(rows: seq[Row], expr: IRExpr): seq[string] =
+proc resolveFrameBounds(pos, partLen: int, frameStart, frameEnd: string): (int, int) =
+  ## Resolve frame boundaries for ROWS mode.
+  ## Returns (startPos, endPos) inclusive within the partition.
+  var startPos = 0
+  var endPos = partLen - 1
+
+  # Parse start boundary
+  if frameStart == "UNBOUNDED PRECEDING":
+    startPos = 0
+  elif frameStart == "CURRENT ROW":
+    startPos = pos
+  elif frameStart.endsWith(" PRECEDING"):
+    let nStr = frameStart[0..^11]
+    var n = 0
+    try: n = parseInt(nStr) except: n = 0
+    startPos = max(0, pos - n)
+  elif frameStart.endsWith(" FOLLOWING"):
+    let nStr = frameStart[0..^11]
+    var n = 0
+    try: n = parseInt(nStr) except: n = 0
+    startPos = min(partLen - 1, pos + n)
+
+  # Parse end boundary
+  if frameEnd == "UNBOUNDED FOLLOWING":
+    endPos = partLen - 1
+  elif frameEnd == "CURRENT ROW":
+    endPos = pos
+  elif frameEnd.endsWith(" PRECEDING"):
+    let nStr = frameEnd[0..^11]
+    var n = 0
+    try: n = parseInt(nStr) except: n = 0
+    endPos = max(0, pos - n)
+  elif frameEnd.endsWith(" FOLLOWING"):
+    let nStr = frameEnd[0..^11]
+    var n = 0
+    try: n = parseInt(nStr) except: n = 0
+    endPos = min(partLen - 1, pos + n)
+
+  if startPos > endPos:
+    startPos = endPos
+  return (startPos, endPos)
+
+proc computeWindowValues*(rows: seq[Row], expr: IRExpr, ctx: ExecutionContext = nil): seq[string] =
   ## Compute a window function for all rows, returning a value per row.
   ## The expr must be of kind irekWindowFunc.
   result = newSeq[string](rows.len)
   if rows.len == 0: return
 
   let wfName = expr.wfName.toLower()
+  let frameMode = expr.wfFrameMode
+  let frameStart = expr.wfFrameStart
+  let frameEnd = expr.wfFrameEnd
 
   # Partition rows
   var groups = initTable[string, seq[int]]()
   for i, row in rows:
-    let pk = partitionKey(row, expr.wfPartition)
+    let pk = partitionKey(row, expr.wfPartition, ctx)
     if pk notin groups:
       groups[pk] = @[]
     groups[pk].add(i)
@@ -1520,7 +1684,7 @@ proc computeWindowValues*(rows: seq[Row], expr: IRExpr): seq[string] =
   for pk, idxs in groups:
     var sortedIdxs = idxs
     sortedIdxs.sort(proc(a, b: int): int =
-      compareRowsByOrder(rows[a], rows[b], expr.wfOrderBy, expr.wfOrderDirs)
+      compareRowsByOrder(rows[a], rows[b], expr.wfOrderBy, expr.wfOrderDirs, ctx)
     )
 
     case wfName
@@ -1531,7 +1695,7 @@ proc computeWindowValues*(rows: seq[Row], expr: IRExpr): seq[string] =
       var currentRank = 1
       for pos, rowIdx in sortedIdxs:
         if pos > 0:
-          let cmpRes = compareRowsByOrder(rows[sortedIdxs[pos - 1]], rows[rowIdx], expr.wfOrderBy, expr.wfOrderDirs)
+          let cmpRes = compareRowsByOrder(rows[sortedIdxs[pos - 1]], rows[rowIdx], expr.wfOrderBy, expr.wfOrderDirs, ctx)
           if cmpRes != 0:
             currentRank = pos + 1
         result[rowIdx] = $currentRank
@@ -1539,14 +1703,14 @@ proc computeWindowValues*(rows: seq[Row], expr: IRExpr): seq[string] =
       var currentRank = 1
       for pos, rowIdx in sortedIdxs:
         if pos > 0:
-          let cmpRes = compareRowsByOrder(rows[sortedIdxs[pos - 1]], rows[rowIdx], expr.wfOrderBy, expr.wfOrderDirs)
+          let cmpRes = compareRowsByOrder(rows[sortedIdxs[pos - 1]], rows[rowIdx], expr.wfOrderBy, expr.wfOrderDirs, ctx)
           if cmpRes != 0:
             currentRank += 1
         result[rowIdx] = $currentRank
     of "ntile":
       var n = 1
       if expr.wfArgs.len > 0:
-        try: n = parseInt(evalExpr(expr.wfArgs[0], rows[sortedIdxs[0]])) except: n = 1
+        try: n = parseInt(evalExpr(expr.wfArgs[0], rows[sortedIdxs[0]], ctx)) except: n = 1
       if n < 1: n = 1
       let groupSize = sortedIdxs.len div n
       let remainder = sortedIdxs.len mod n
@@ -1565,36 +1729,36 @@ proc computeWindowValues*(rows: seq[Row], expr: IRExpr): seq[string] =
       var offset = 1
       var defaultVal = ""
       if expr.wfArgs.len > 1:
-        try: offset = parseInt(evalExpr(expr.wfArgs[1], rows[sortedIdxs[0]])) except: offset = 1
+        try: offset = parseInt(evalExpr(expr.wfArgs[1], rows[sortedIdxs[0]], ctx)) except: offset = 1
       if expr.wfArgs.len > 2:
-        defaultVal = evalExpr(expr.wfArgs[2], rows[sortedIdxs[0]])
+        defaultVal = evalExpr(expr.wfArgs[2], rows[sortedIdxs[0]], ctx)
       for pos, rowIdx in sortedIdxs:
         let targetPos = pos + offset
         if targetPos < sortedIdxs.len:
-          result[rowIdx] = evalExpr(expr.wfArgs[0], rows[sortedIdxs[targetPos]])
+          result[rowIdx] = evalExpr(expr.wfArgs[0], rows[sortedIdxs[targetPos]], ctx)
         else:
           result[rowIdx] = defaultVal
     of "lag":
       var offset = 1
       var defaultVal = ""
       if expr.wfArgs.len > 1:
-        try: offset = parseInt(evalExpr(expr.wfArgs[1], rows[sortedIdxs[0]])) except: offset = 1
+        try: offset = parseInt(evalExpr(expr.wfArgs[1], rows[sortedIdxs[0]], ctx)) except: offset = 1
       if expr.wfArgs.len > 2:
-        defaultVal = evalExpr(expr.wfArgs[2], rows[sortedIdxs[0]])
+        defaultVal = evalExpr(expr.wfArgs[2], rows[sortedIdxs[0]], ctx)
       for pos, rowIdx in sortedIdxs:
         let targetPos = pos - offset
         if targetPos >= 0:
-          result[rowIdx] = evalExpr(expr.wfArgs[0], rows[sortedIdxs[targetPos]])
+          result[rowIdx] = evalExpr(expr.wfArgs[0], rows[sortedIdxs[targetPos]], ctx)
         else:
           result[rowIdx] = defaultVal
     of "first_value":
-      let firstVal = evalExpr(expr.wfArgs[0], rows[sortedIdxs[0]])
-      for rowIdx in sortedIdxs:
-        result[rowIdx] = firstVal
+      for pos, rowIdx in sortedIdxs:
+        let (fStart, fEnd) = resolveFrameBounds(pos, sortedIdxs.len, frameStart, frameEnd)
+        result[rowIdx] = evalExpr(expr.wfArgs[0], rows[sortedIdxs[fStart]], ctx)
     of "last_value":
-      let lastVal = evalExpr(expr.wfArgs[0], rows[sortedIdxs[^1]])
-      for rowIdx in sortedIdxs:
-        result[rowIdx] = lastVal
+      for pos, rowIdx in sortedIdxs:
+        let (fStart, fEnd) = resolveFrameBounds(pos, sortedIdxs.len, frameStart, frameEnd)
+        result[rowIdx] = evalExpr(expr.wfArgs[0], rows[sortedIdxs[fEnd]], ctx)
     else:
       # Unknown window function — fill with empty
       for rowIdx in sortedIdxs:
@@ -1621,8 +1785,12 @@ proc executePlan*(ctx: ExecutionContext, plan: IRPlan): seq[Row] =
         result.add(row)
 
   of irpkProject:
-    let sourceRows = executePlan(ctx, plan.projectSource)
+    var sourceRows = executePlan(ctx, plan.projectSource)
     if plan.projectAliases.len == 0: return sourceRows
+    # Scalar SELECT (no FROM): create a dummy row so expressions can be evaluated
+    if sourceRows.len == 0 and plan.projectSource != nil and
+       plan.projectSource.kind == irpkScan and plan.projectSource.scanTable.len == 0:
+      sourceRows = @[initTable[string, string]()]
 
     # Check if this projection contains aggregates without GROUP BY
     var hasAggs = false
@@ -1660,7 +1828,7 @@ proc executePlan*(ctx: ExecutionContext, plan: IRPlan): seq[Row] =
                 if not k.startsWith("$") and not k.contains("."):
                   newRow[k] = v
             else:
-              let val = evalExpr(expr, row)
+              let val = evalExpr(expr, row, ctx)
               if alias.len > 0: newRow[alias] = val
               else: newRow["col" & $i] = val
         if newRow.len > 0:
@@ -1686,7 +1854,7 @@ proc executePlan*(ctx: ExecutionContext, plan: IRPlan): seq[Row] =
             if expr.aggFilter != nil:
               filteredRows = @[]
               for row in sourceRows:
-                if evalExpr(expr.aggFilter, row) == "true":
+                if evalExpr(expr.aggFilter, row, ctx) == "true":
                   filteredRows.add(row)
             case expr.aggOp
             of irCount:
@@ -1695,49 +1863,49 @@ proc executePlan*(ctx: ExecutionContext, plan: IRPlan): seq[Row] =
               else:
                 var count = 0
                 for row in filteredRows:
-                  let v = evalExpr(expr.aggArgs[0], row)
+                  let v = evalExpr(expr.aggArgs[0], row, ctx)
                   if v.len > 0: count += 1
                 newRow[alias] = $count
             of irSum:
               var sum = 0.0
               for row in filteredRows:
-                let v = evalExpr(expr.aggArgs[0], row)
+                let v = evalExpr(expr.aggArgs[0], row, ctx)
                 try: sum += parseFloat(v) except: discard
               newRow[alias] = $sum
             of irAvg:
               var sum = 0.0
               var count = 0
               for row in filteredRows:
-                let v = evalExpr(expr.aggArgs[0], row)
+                let v = evalExpr(expr.aggArgs[0], row, ctx)
                 try: sum += parseFloat(v); count += 1 except: discard
               newRow[alias] = if count > 0: $(sum / float(count)) else: "0"
             of irMin:
               var minVal = ""
               for row in filteredRows:
-                let v = evalExpr(expr.aggArgs[0], row)
+                let v = evalExpr(expr.aggArgs[0], row, ctx)
                 if minVal == "" or v < minVal: minVal = v
               newRow[alias] = minVal
             of irMax:
               var maxVal = ""
               for row in filteredRows:
-                let v = evalExpr(expr.aggArgs[0], row)
+                let v = evalExpr(expr.aggArgs[0], row, ctx)
                 if maxVal == "" or v > maxVal: maxVal = v
               newRow[alias] = maxVal
             of irArrayAgg:
               var arr: seq[string]
               for row in filteredRows:
                 if expr.aggArgs.len > 0:
-                  arr.add(evalExpr(expr.aggArgs[0], row))
+                  arr.add(evalExpr(expr.aggArgs[0], row, ctx))
               newRow[alias] = "[" & arr.join(", ") & "]"
             of irStringAgg:
               var parts: seq[string]
-              let delim = if expr.aggArgs.len > 1: evalExpr(expr.aggArgs[1], initTable[string, string]()) else: ","
+              let delim = if expr.aggArgs.len > 1: evalExpr(expr.aggArgs[1], initTable[string, string](), ctx) else: ","
               for row in filteredRows:
                 if expr.aggArgs.len > 0:
-                  parts.add(evalExpr(expr.aggArgs[0], row))
+                  parts.add(evalExpr(expr.aggArgs[0], row, ctx))
               newRow[alias] = parts.join(delim)
           else:
-            let val = evalExpr(expr, if sourceRows.len > 0: sourceRows[0] else: initTable[string, string]())
+            let val = evalExpr(expr, if sourceRows.len > 0: sourceRows[0] else: initTable[string, string](), ctx)
             if alias.len > 0: newRow[alias] = val
             else: newRow["col" & $i] = val
       result = @[newRow]
@@ -1768,7 +1936,7 @@ proc executePlan*(ctx: ExecutionContext, plan: IRPlan): seq[Row] =
               if alias.len > 0: newRow[alias] = "0"
               else: newRow["col" & $i] = "0"
           else:
-            let val = evalExpr(expr, row)
+            let val = evalExpr(expr, row, ctx)
             if alias.len > 0: newRow[alias] = val
             else: newRow["col" & $i] = val
       if newRow.len > 0:
@@ -1782,8 +1950,8 @@ proc executePlan*(ctx: ExecutionContext, plan: IRPlan): seq[Row] =
     let sortExpr = plan.sortExprs[0]
     let ascending = if plan.sortDirs.len > 0: plan.sortDirs[0] else: true
     proc sortCmp(a, b: Row): int =
-      let va = evalExpr(sortExpr, a)
-      let vb = evalExpr(sortExpr, b)
+      let va = evalExpr(sortExpr, a, ctx)
+      let vb = evalExpr(sortExpr, b, ctx)
       try:
         let fa = parseFloat(va)
         let fb = parseFloat(vb)
@@ -1839,7 +2007,7 @@ proc executePlan*(ctx: ExecutionContext, plan: IRPlan): seq[Row] =
       for row in sourceRows:
         var groupKey = ""
         for gk in gkeys:
-          groupKey &= evalExpr(gk, row) & "|"
+          groupKey &= evalExpr(gk, row, ctx) & "|"
         if groupKey notin groups:
           groups[groupKey] = @[]
         groups[groupKey].add(row)
@@ -1847,7 +2015,7 @@ proc executePlan*(ctx: ExecutionContext, plan: IRPlan): seq[Row] =
         var aggRow: Table[string, string]
         for gkExpr in gkeys:
           if gkExpr.kind == irekField and gkExpr.fieldPath.len > 0:
-            aggRow[gkExpr.fieldPath[^1]] = evalExpr(gkExpr, groupRows[0])
+            aggRow[gkExpr.fieldPath[^1]] = evalExpr(gkExpr, groupRows[0], ctx)
         # Compute each aggregate expression
         for aggExpr in plan.groupAggs:
           let aggKey = "$agg_" & $aggExpr.aggOp & "_" & $plan.groupAggs.find(aggExpr)
@@ -1855,7 +2023,7 @@ proc executePlan*(ctx: ExecutionContext, plan: IRPlan): seq[Row] =
           if aggExpr.aggFilter != nil:
             filteredRows = @[]
             for row in groupRows:
-              if evalExpr(aggExpr.aggFilter, row) == "true":
+              if evalExpr(aggExpr.aggFilter, row, ctx) == "true":
                 filteredRows.add(row)
           case aggExpr.aggOp
           of irCount:
@@ -1864,50 +2032,50 @@ proc executePlan*(ctx: ExecutionContext, plan: IRPlan): seq[Row] =
             else:
               var count = 0
               for row in filteredRows:
-                let v = evalExpr(aggExpr.aggArgs[0], row)
+                let v = evalExpr(aggExpr.aggArgs[0], row, ctx)
                 if v.len > 0: count += 1
               aggRow[aggKey] = $count
           of irSum:
             var sum = 0.0
             for row in filteredRows:
-              let v = evalExpr(aggExpr.aggArgs[0], row)
+              let v = evalExpr(aggExpr.aggArgs[0], row, ctx)
               try: sum += parseFloat(v) except: discard
             aggRow[aggKey] = $sum
           of irAvg:
             var sum = 0.0
             var count = 0
             for row in filteredRows:
-              let v = evalExpr(aggExpr.aggArgs[0], row)
+              let v = evalExpr(aggExpr.aggArgs[0], row, ctx)
               try: sum += parseFloat(v); count += 1 except: discard
             aggRow[aggKey] = if count > 0: $(sum / float(count)) else: "0"
           of irMin:
             var minVal = ""
             for row in filteredRows:
-              let v = evalExpr(aggExpr.aggArgs[0], row)
+              let v = evalExpr(aggExpr.aggArgs[0], row, ctx)
               if minVal == "" or v < minVal: minVal = v
             aggRow[aggKey] = minVal
           of irMax:
             var maxVal = ""
             for row in filteredRows:
-              let v = evalExpr(aggExpr.aggArgs[0], row)
+              let v = evalExpr(aggExpr.aggArgs[0], row, ctx)
               if maxVal == "" or v > maxVal: maxVal = v
             aggRow[aggKey] = maxVal
           of irArrayAgg:
             var arr: seq[string]
             for row in filteredRows:
               if aggExpr.aggArgs.len > 0:
-                arr.add(evalExpr(aggExpr.aggArgs[0], row))
+                arr.add(evalExpr(aggExpr.aggArgs[0], row, ctx))
             aggRow[aggKey] = "[" & arr.join(", ") & "]"
           of irStringAgg:
             var parts: seq[string]
-            let delim = if aggExpr.aggArgs.len > 1: evalExpr(aggExpr.aggArgs[1], initTable[string, string]()) else: ","
+            let delim = if aggExpr.aggArgs.len > 1: evalExpr(aggExpr.aggArgs[1], initTable[string, string](), ctx) else: ","
             for row in filteredRows:
               if aggExpr.aggArgs.len > 0:
-                parts.add(evalExpr(aggExpr.aggArgs[0], row))
+                parts.add(evalExpr(aggExpr.aggArgs[0], row, ctx))
             aggRow[aggKey] = parts.join(delim)
         # Apply HAVING filter
         if plan.groupHaving != nil:
-          if evalExpr(plan.groupHaving, aggRow) != "true":
+          if evalExpr(plan.groupHaving, aggRow, ctx) != "true":
             continue
         result.add(aggRow)
     return result
@@ -1979,9 +2147,9 @@ proc executePlan*(ctx: ExecutionContext, plan: IRPlan): seq[Row] =
         var mergedRows: seq[Row]
         for r in rawRightRows:
           let merged = mergeRow(l, r, leftAlias, rightAlias)
-          if rightFilter != nil and evalExpr(rightFilter, merged) != "true":
+          if rightFilter != nil and evalExpr(rightFilter, merged, ctx) != "true":
             continue
-          if plan.joinCond != nil and evalExpr(plan.joinCond, merged) != "true":
+          if plan.joinCond != nil and evalExpr(plan.joinCond, merged, ctx) != "true":
             continue
           mergedRows.add(merged)
 
@@ -1989,8 +2157,8 @@ proc executePlan*(ctx: ExecutionContext, plan: IRPlan): seq[Row] =
         if rightSortExprs.len > 0 and mergedRows.len > 1:
           mergedRows.sort(proc(a, b: Row): int =
             for i, sExpr in rightSortExprs:
-              let aVal = evalExpr(sExpr, a)
-              let bVal = evalExpr(sExpr, b)
+              let aVal = evalExpr(sExpr, a, ctx)
+              let bVal = evalExpr(sExpr, b, ctx)
               let asc = if i < rightSortDirs.len: rightSortDirs[i] else: true
               var cmp = 0
               let aNum = parseFloat(aVal)
@@ -2060,7 +2228,7 @@ proc executePlan*(ctx: ExecutionContext, plan: IRPlan): seq[Row] =
       var matched = false
       for r in rightRows:
         let merged = mergeRow(l, r, leftAlias, rightAlias)
-        if plan.joinCond == nil or evalExpr(plan.joinCond, merged) == "true":
+        if plan.joinCond == nil or evalExpr(plan.joinCond, merged, ctx) == "true":
           result.add(merged)
           matched = true
       if not matched and (plan.joinKind == irjkLeft or plan.joinKind == irjkFull):
@@ -2084,7 +2252,7 @@ proc executePlan*(ctx: ExecutionContext, plan: IRPlan): seq[Row] =
         var found = false
         for l in leftRows:
           let merged = mergeRow(l, r, leftAlias, rightAlias)
-          if plan.joinCond == nil or evalExpr(plan.joinCond, merged) == "true":
+          if plan.joinCond == nil or evalExpr(plan.joinCond, merged, ctx) == "true":
             found = true
             break
         if not found:
@@ -2152,32 +2320,32 @@ proc executePlan*(ctx: ExecutionContext, plan: IRPlan): seq[Row] =
             else:
               var count = 0
               for row in matchingRows:
-                let v = evalExpr(plan.pivotAgg.aggArgs[0], row)
+                let v = evalExpr(plan.pivotAgg.aggArgs[0], row, ctx)
                 if v.len > 0: count += 1
               aggResult = $count
           of irSum:
             var sum = 0.0
             for row in matchingRows:
-              let v = evalExpr(plan.pivotAgg.aggArgs[0], row)
+              let v = evalExpr(plan.pivotAgg.aggArgs[0], row, ctx)
               try: sum += parseFloat(v) except: discard
             aggResult = $sum
           of irAvg:
             var sum = 0.0
             var count = 0
             for row in matchingRows:
-              let v = evalExpr(plan.pivotAgg.aggArgs[0], row)
+              let v = evalExpr(plan.pivotAgg.aggArgs[0], row, ctx)
               try: sum += parseFloat(v); count += 1 except: discard
             aggResult = if count > 0: $(sum / float(count)) else: "0"
           of irMin:
             var minVal = ""
             for row in matchingRows:
-              let v = evalExpr(plan.pivotAgg.aggArgs[0], row)
+              let v = evalExpr(plan.pivotAgg.aggArgs[0], row, ctx)
               if minVal == "" or v < minVal: minVal = v
             aggResult = minVal
           of irMax:
             var maxVal = ""
             for row in matchingRows:
-              let v = evalExpr(plan.pivotAgg.aggArgs[0], row)
+              let v = evalExpr(plan.pivotAgg.aggArgs[0], row, ctx)
               if maxVal == "" or v > maxVal: maxVal = v
             aggResult = maxVal
           else: discard
@@ -2469,15 +2637,15 @@ proc executeQuery*(ctx: ExecutionContext, astNode: Node, params: seq[WireValue]
           let whereIr = lowerExpr(stmt.selWhere.whereExpr)
           var tmp: seq[Row] = @[]
           for row in filteredRows:
-            if evalExpr(whereIr, row) == "true":
+            if evalExpr(whereIr, row, ctx) == "true":
               tmp.add(row)
           filteredRows = tmp
         if stmt.selOrderBy.len > 0:
           let sortExpr = lowerExpr(stmt.selOrderBy[0].orderByExpr)
           let asc = stmt.selOrderBy[0].orderByDir == sdAsc
           proc sortCmp(a, b: Row): int =
-            let va = evalExpr(sortExpr, a)
-            let vb = evalExpr(sortExpr, b)
+            let va = evalExpr(sortExpr, a, ctx)
+            let vb = evalExpr(sortExpr, b, ctx)
             try:
               let fa = parseFloat(va)
               let fb = parseFloat(vb)
@@ -2798,7 +2966,7 @@ proc executeQuery*(ctx: ExecutionContext, astNode: Node, params: seq[WireValue]
       # Check WHERE
       if stmt.updWhere != nil and stmt.updWhere.whereExpr != nil:
         let whereExpr = lowerExpr(stmt.updWhere.whereExpr)
-        if evalExpr(whereExpr, row) != "true": continue
+        if evalExpr(whereExpr, row, ctx) != "true": continue
       # Get key from row
       if "$key" in row:
         let old = row["$key"]
@@ -2839,7 +3007,7 @@ proc executeQuery*(ctx: ExecutionContext, astNode: Node, params: seq[WireValue]
     for row in rows:
       if stmt.delWhere != nil and stmt.delWhere.whereExpr != nil:
         let whereExpr = lowerExpr(stmt.delWhere.whereExpr)
-        if evalExpr(whereExpr, row) != "true": continue
+        if evalExpr(whereExpr, row, ctx) != "true": continue
       if "$key" in row:
         let old = row["$key"]
         # Fire BEFORE DELETE triggers
@@ -2879,7 +3047,7 @@ proc executeQuery*(ctx: ExecutionContext, astNode: Node, params: seq[WireValue]
         for k, v in tgtRow:
           rowWithTarget[stmt.mergeTargetAlias & "." & k] = v
         let onExpr = lowerExpr(stmt.mergeOn)
-        if evalExpr(onExpr, rowWithTarget) == "true":
+        if evalExpr(onExpr, rowWithTarget, ctx) == "true":
           matched = true
           if stmt.mergeMatchedUpdate.len > 0 and "$key" in tgtRow:
             var updateSets = initTable[string, string]()
@@ -2887,7 +3055,7 @@ proc executeQuery*(ctx: ExecutionContext, astNode: Node, params: seq[WireValue]
               if s.kind == nkBinOp and s.binOp == bkAssign:
                 if s.binLeft.kind == nkIdent:
                   let valExpr = lowerExpr(s.binRight)
-                  updateSets[s.binLeft.identName] = evalExpr(valExpr, rowWithTarget)
+                  updateSets[s.binLeft.identName] = evalExpr(valExpr, rowWithTarget, ctx)
             var newRow = tgtRow
             for col, val in updateSets:
               newRow[col] = val
@@ -2907,7 +3075,7 @@ proc executeQuery*(ctx: ExecutionContext, astNode: Node, params: seq[WireValue]
             if i < stmt.mergeNotMatchedValues.len:
               let v = stmt.mergeNotMatchedValues[i]
               let valExpr = lowerExpr(v)
-              values.add(evalExpr(valExpr, combinedRow))
+              values.add(evalExpr(valExpr, combinedRow, ctx))
             else:
               values.add("")
         if fields.len > 0:
@@ -3284,14 +3452,16 @@ proc executeQuery*(ctx: ExecutionContext, astNode: Node, params: seq[WireValue]
       # Full-text search index
       var ftsIdx = fts.newInvertedIndex()
       let rows = execScan(ctx, stmt.ciTarget)
-      var docId: uint64 = 0
       for row in rows:
+        let lsmKey = if "$key" in row: row["$key"] else: ""
+        let docKey = stmt.ciTarget & "." & lsmKey
+        var docId: uint64 = 0
+        for ch in docKey:
+          docId = docId * 31 + uint64(ord(ch))
         for col in stmt.ciColumns:
           let text = if col in row: row[col] else: ""
           if text.len > 0:
             ftsIdx.addDocument(docId, text)
-        let lsmKey = if "$key" in row: row["$key"] else: ""
-        docId += 1
       ctx.ftsIndexes[colKey] = ftsIdx
       return okResult(msg="CREATE INDEX " & idxName & " on " & stmt.ciTarget & " USING FTS")
 
@@ -3426,6 +3596,10 @@ proc executeQuery*(ctx: ExecutionContext, astNode: Node, params: seq[WireValue]
     ctx.db.delete(grantKey)
     return okResult(msg="REVOKE " & stmt.rvPrivilege & " ON " & stmt.rvTable & " FROM " & stmt.rvGrantee)
 
+  of nkSetVar:
+    ctx.sessionVars[stmt.svName] = stmt.svValue
+    return okResult(msg="SET " & stmt.svName & " = " & stmt.svValue)
+
   else:
     return errResult("Unsupported statement type: " & $stmt.kind)
 
diff --git a/src/barabadb/query/ir.nim b/src/barabadb/query/ir.nim
index 5af20c4..141d492 100644
--- a/src/barabadb/query/ir.nim
+++ b/src/barabadb/query/ir.nim
@@ -29,6 +29,10 @@ type
     irIsNull, irIsNotNull
     irFtsMatch
     irDistance
+    irJsonContains
+    irJsonContainedBy
+    irJsonHasAny
+    irJsonHasAll
 
   IRAggregate* = enum
     irCount, irSum, irAvg, irMin, irMax
diff --git a/src/barabadb/query/lexer.nim b/src/barabadb/query/lexer.nim
index f466fc5..2a04207 100644
--- a/src/barabadb/query/lexer.nim
+++ b/src/barabadb/query/lexer.nim
@@ -147,6 +147,10 @@ type
     tkArrowR       # ->
     tkArrowRR      # ->>
     tkFtsMatch     # @@
+    tkJsonContains # @>
+    tkJsonContainedBy # <@
+    tkJsonHasAny   # ?|
+    tkJsonHasAll   # ?&
     tkSimilar
     tkNearest
     tkTo
@@ -157,12 +161,15 @@ type
     # Window functions
     tkOver
     tkPartition
+    tkRow
     tkRows
     tkRange
     tkUnbounded
     tkPreceding
     tkFollowing
     tkCurrent
+    tkCurrentUser
+    tkCurrentRole
     tkRowNumber
     tkRank
     tkDenseRank
@@ -365,12 +372,15 @@ const keywords*: Table[string, TokenKind] = {
   "path": tkPath,
   "over": tkOver,
   "partition": tkPartition,
+  "row": tkRow,
   "rows": tkRows,
   "range": tkRange,
   "unbounded": tkUnbounded,
   "preceding": tkPreceding,
   "following": tkFollowing,
   "current": tkCurrent,
+  "current_user": tkCurrentUser,
+  "current_role": tkCurrentRole,
   "row_number": tkRowNumber,
   "rank": tkRank,
   "dense_rank": tkDenseRank,
@@ -586,6 +596,10 @@ proc nextToken*(l: var Lexer): Token =
       discard l.advance()
       discard l.advance()
       return Token(kind: tkNotEq, value: "<>", line: startLine, col: startCol)
+    if l.pos + 1 < l.input.len and l.input[l.pos + 1] == '@':
+      discard l.advance()
+      discard l.advance()
+      return Token(kind: tkJsonContainedBy, value: "<@", line: startLine, col: startCol)
     discard l.advance()
     return Token(kind: tkLt, value: "<", line: startLine, col: startCol)
   of '>':
@@ -596,6 +610,16 @@ proc nextToken*(l: var Lexer): Token =
     discard l.advance()
     return Token(kind: tkGt, value: ">", line: startLine, col: startCol)
   of '?':
+    if l.pos + 2 < l.input.len and l.input[l.pos + 1] == '|':
+      discard l.advance()
+      discard l.advance()
+      discard l.advance()
+      return Token(kind: tkJsonHasAny, value: "?|", line: startLine, col: startCol)
+    if l.pos + 2 < l.input.len and l.input[l.pos + 1] == '&':
+      discard l.advance()
+      discard l.advance()
+      discard l.advance()
+      return Token(kind: tkJsonHasAll, value: "?&", line: startLine, col: startCol)
     if l.pos + 1 < l.input.len and l.input[l.pos + 1] == '?':
       discard l.advance()
       discard l.advance()
@@ -607,6 +631,10 @@ proc nextToken*(l: var Lexer): Token =
       discard l.advance()
       discard l.advance()
       return Token(kind: tkFtsMatch, value: "@@", line: startLine, col: startCol)
+    if l.pos + 1 < l.input.len and l.input[l.pos + 1] == '>':
+      discard l.advance()
+      discard l.advance()
+      return Token(kind: tkJsonContains, value: "@>", line: startLine, col: startCol)
     discard l.advance()
     return Token(kind: tkInvalid, value: "@", line: startLine, col: startCol)
   of '.':
diff --git a/src/barabadb/query/parser.nim b/src/barabadb/query/parser.nim
index 97babec..85c84bb 100644
--- a/src/barabadb/query/parser.nim
+++ b/src/barabadb/query/parser.nim
@@ -41,6 +41,7 @@ proc parseCreateType(p: var Parser): Node
 proc parseOverClause(p: var Parser): Node
 proc parseFrameSpec(p: var Parser): Node
 proc parseFrameBoundary(p: var Parser): string
+proc parseSetVar(p: var Parser): Node
 
 proc parsePrimary(p: var Parser): Node =
   let tok = p.peek()
@@ -60,6 +61,12 @@ proc parsePrimary(p: var Parser): Node =
   of tkNull:
     discard p.advance()
     Node(kind: nkNullLit, line: tok.line, col: tok.col)
+  of tkCurrentUser:
+    discard p.advance()
+    Node(kind: nkCurrentUser, line: tok.line, col: tok.col)
+  of tkCurrentRole:
+    discard p.advance()
+    Node(kind: nkCurrentRole, line: tok.line, col: tok.col)
   of tkIdent, tkRowNumber, tkRank, tkDenseRank, tkLead, tkLag, tkFirstValue, tkLastValue, tkNtile:
     discard p.advance()
     let funcName = tok.value
@@ -231,7 +238,7 @@ proc parseFrameBoundary(p: var Parser): string =
     else:
       raise newException(ValueError, "Expected PRECEDING or FOLLOWING after UNBOUNDED")
   elif p.match(tkCurrent):
-    discard p.expect(tkRows)
+    discard p.expect(tkRow)
     return "CURRENT ROW"
   else:
     # Expect a simple integer literal for offset boundaries
@@ -318,7 +325,7 @@ proc parseComparison(p: var Parser): Node =
     discard p.advance()  # consume NULL token (assumed)
     return Node(kind: nkIsExpr, isExpr: result, isNegated: negated,
                 line: tok.line, col: tok.col)
-  while p.peek().kind in {tkEq, tkNotEq, tkLt, tkLtEq, tkGt, tkGtEq, tkFtsMatch, tkDistanceOp}:
+  while p.peek().kind in {tkEq, tkNotEq, tkLt, tkLtEq, tkGt, tkGtEq, tkFtsMatch, tkDistanceOp, tkJsonContains, tkJsonContainedBy, tkJsonHasAny, tkJsonHasAll}:
     let op = case p.peek().kind
       of tkEq: bkEq
       of tkNotEq: bkNotEq
@@ -328,6 +335,10 @@ proc parseComparison(p: var Parser): Node =
       of tkGtEq: bkGtEq
       of tkFtsMatch: bkFtsMatch
       of tkDistanceOp: bkDistance
+      of tkJsonContains: bkJsonContains
+      of tkJsonContainedBy: bkJsonContainedBy
+      of tkJsonHasAny: bkJsonHasAny
+      of tkJsonHasAll: bkJsonHasAll
       else: bkEq
     let tok = p.advance()
     let right = p.parseAddSub()
@@ -1056,13 +1067,13 @@ proc parseAlterTable(p: var Parser): Node =
   # Check for ENABLE/DISABLE ROW LEVEL SECURITY
   if p.peek().kind == tkEnable:
     discard p.advance()
-    discard p.expect(tkIdent)  # ROW
+    discard p.expect(tkRow)    # ROW
     discard p.expect(tkIdent)  # LEVEL
     discard p.expect(tkIdent)  # SECURITY
     return Node(kind: nkEnableRLS, erlsTable: tableName, line: tok.line, col: tok.col)
   elif p.peek().kind == tkDisable:
     discard p.advance()
-    discard p.expect(tkIdent)  # ROW
+    discard p.expect(tkRow)    # ROW
     discard p.expect(tkIdent)  # LEVEL
     discard p.expect(tkIdent)  # SECURITY
     return Node(kind: nkDisableRLS, drlsTable: tableName, line: tok.line, col: tok.col)
@@ -1422,6 +1433,35 @@ proc parseRevoke(p: var Parser): Node =
   result = Node(kind: nkRevoke, rvPrivilege: priv, rvTable: tableName,
                 rvGrantee: grantee, line: tok.line, col: tok.col)
 
+proc parseSetVar(p: var Parser): Node =
+  let tok = p.expect(tkSet)
+  var varName = p.expect(tkIdent).value
+  while p.peek().kind == tkDot:
+    discard p.advance()
+    varName.add(".")
+    varName.add(p.expect(tkIdent).value)
+  if p.match(tkEq) or p.match(tkTo):
+    discard
+  let valTok = p.peek()
+  var valStr = ""
+  case valTok.kind
+  of tkStringLit:
+    valStr = valTok.value
+    discard p.advance()
+  of tkIntLit:
+    valStr = valTok.value
+    discard p.advance()
+  of tkFloatLit:
+    valStr = valTok.value
+    discard p.advance()
+  of tkIdent:
+    valStr = valTok.value
+    discard p.advance()
+  else:
+    raise newException(ValueError, "Expected value after SET " & varName)
+  result = Node(kind: nkSetVar, svName: varName, svValue: valStr,
+                line: tok.line, col: tok.col)
+
 proc parseStatement*(p: var Parser): Node =
   case p.peek().kind
   of tkWith, tkSelect: p.parseSelect()
@@ -1483,6 +1523,8 @@ proc parseStatement*(p: var Parser): Node =
     p.parseGrant()
   of tkRevoke:
     p.parseRevoke()
+  of tkSet:
+    p.parseSetVar()
   of tkApply:
     if p.pos + 1 < p.tokens.len and p.tokens[p.pos + 1].kind == tkMigration:
       p.parseApplyMigration()
diff --git a/tests/test_all.nim b/tests/test_all.nim
index 59ec246..6199b57 100644
--- a/tests/test_all.nim
+++ b/tests/test_all.nim
@@ -2287,6 +2287,69 @@ suite "Row-Level Security":
     check res.success
     check res.rows.len == 1  # superuser sees all (only 1 row exists)
 
+suite "Session Variables and Multi-Tenant":
+  test "SET statement parse":
+    let ast = parse("SET app.tenant_id = 'company-123'")
+    check ast.stmts.len == 1
+    check ast.stmts[0].kind == nkSetVar
+    check ast.stmts[0].svName == "app.tenant_id"
+    check ast.stmts[0].svValue == "company-123"
+
+  test "SET and current_setting":
+    let tmpDir = getTempDir() / "baradb_session_test_" & $getMonoTime().ticks
+    var db = newLSMTree(tmpDir)
+    var ctx = qexec.newExecutionContext(db)
+    discard qexec.executeQuery(ctx, parse("SET app.tenant_id = 'company-123'"))
+    let r = qexec.executeQuery(ctx, parse("SELECT current_setting('app.tenant_id') AS tenant"))
+    check r.success
+    check r.rows.len == 1
+    check r.rows[0]["tenant"] == "company-123"
+
+  test "current_user in SELECT":
+    let tmpDir = getTempDir() / "baradb_user_test_" & $getMonoTime().ticks
+    var db = newLSMTree(tmpDir)
+    var ctx = qexec.newExecutionContext(db)
+    ctx.currentUser = "alice"
+    let r = qexec.executeQuery(ctx, parse("SELECT current_user AS me"))
+    check r.success
+    check r.rows.len == 1
+    check r.rows[0]["me"] == "alice"
+
+  test "current_role in SELECT":
+    let tmpDir = getTempDir() / "baradb_role_test_" & $getMonoTime().ticks
+    var db = newLSMTree(tmpDir)
+    var ctx = qexec.newExecutionContext(db)
+    ctx.currentRole = "admin"
+    let r = qexec.executeQuery(ctx, parse("SELECT current_role AS role"))
+    check r.success
+    check r.rows.len == 1
+    check r.rows[0]["role"] == "admin"
+
+  test "Multi-tenant RLS with current_setting":
+    let tmpDir = getTempDir() / "baradb_multitenant_test_" & $getMonoTime().ticks
+    var db = newLSMTree(tmpDir)
+    var ctx = qexec.newExecutionContext(db)
+    discard qexec.executeQuery(ctx, parse("CREATE TABLE invoices (id INTEGER, tenant_id TEXT, amount INT)"))
+    discard qexec.executeQuery(ctx, parse("INSERT INTO invoices (id, tenant_id, amount) VALUES (1, 'company-a', 100)"))
+    discard qexec.executeQuery(ctx, parse("INSERT INTO invoices (id, tenant_id, amount) VALUES (2, 'company-b', 200)"))
+    # Set session variable for tenant
+    discard qexec.executeQuery(ctx, parse("SET app.tenant_id = 'company-a'"))
+    # Create policy that uses current_setting
+    ctx.users["app"] = qexec.UserDef(name: "app", passwordHash: "", isSuperuser: false, roles: @[])
+    ctx.currentUser = "app"
+    ctx.policies["invoices"] = @[
+      qexec.PolicyDef(name: "tenant_isolation", tableName: "invoices", command: "SELECT",
+                usingExpr: Node(kind: nkBinOp, binOp: bkEq,
+                  binLeft: Node(kind: nkIdent, identName: "tenant_id"),
+                  binRight: Node(kind: nkFuncCall, funcName: "current_setting",
+                    funcArgs: @[Node(kind: nkStringLit, strVal: "app.tenant_id")])),
+                withCheckExpr: nil)
+    ]
+    let r = qexec.executeQuery(ctx, parse("SELECT id, tenant_id FROM invoices"))
+    check r.success
+    check r.rows.len == 1
+    check r.rows[0]["tenant_id"] == "company-a"
+
 suite "UTF-8 Support":
   test "Tokenize UTF-8 identifiers":
     let tokens = lex.tokenize("SELECT имя FROM потребители")
@@ -2303,7 +2366,8 @@ suite "UTF-8 Support":
     check ast.stmts[0].selWhere.whereExpr.binRight.strVal == "София"
 
   test "Execute query with UTF-8 data":
-    var db = newLSMTree("")
+    let tmpDir = getTempDir() / "baradb_test_" & $getMonoTime().ticks
+    var db = newLSMTree(tmpDir)
     var ctx = qexec.newExecutionContext(db)
     discard qexec.executeQuery(ctx, parse("CREATE TABLE потребители (имя TEXT, град TEXT)"))
     discard qexec.executeQuery(ctx, parse("INSERT INTO потребители (имя, град) VALUES ('Иван', 'София'), ('Мария', 'Пловдив')"))
@@ -2315,7 +2379,8 @@ suite "UTF-8 Support":
 
 suite "B-Tree Range Scan":
   test "BETWEEN uses index range scan":
-    var db = newLSMTree("")
+    let tmpDir = getTempDir() / "baradb_test_" & $getMonoTime().ticks
+    var db = newLSMTree(tmpDir)
     var ctx = qexec.newExecutionContext(db)
     discard qexec.executeQuery(ctx, parse("CREATE TABLE products (id INTEGER, name TEXT)"))
     discard qexec.executeQuery(ctx, parse("INSERT INTO products (id, name) VALUES (1, 'apple'), (2, 'banana'), (3, 'cherry'), (4, 'date'), (5, 'elderberry')"))
@@ -2325,7 +2390,8 @@ suite "B-Tree Range Scan":
     check res.rows.len == 3
 
   test "Greater than uses index range scan":
-    var db = newLSMTree("")
+    let tmpDir = getTempDir() / "baradb_test_" & $getMonoTime().ticks
+    var db = newLSMTree(tmpDir)
     var ctx = qexec.newExecutionContext(db)
     discard qexec.executeQuery(ctx, parse("CREATE TABLE nums (id INTEGER, val TEXT)"))
     discard qexec.executeQuery(ctx, parse("INSERT INTO nums (id, val) VALUES (1, '10'), (2, '20'), (3, '30'), (4, '40'), (5, '50')"))
@@ -2335,7 +2401,8 @@ suite "B-Tree Range Scan":
     check res.rows.len == 3
 
   test "Less than or equal uses index range scan":
-    var db = newLSMTree("")
+    let tmpDir = getTempDir() / "baradb_test_" & $getMonoTime().ticks
+    var db = newLSMTree(tmpDir)
     var ctx = qexec.newExecutionContext(db)
     discard qexec.executeQuery(ctx, parse("CREATE TABLE nums2 (id INTEGER, val TEXT)"))
     discard qexec.executeQuery(ctx, parse("INSERT INTO nums2 (id, val) VALUES (1, '10'), (2, '20'), (3, '30'), (4, '40'), (5, '50')"))
@@ -2458,13 +2525,18 @@ suite "Enhanced Migrations":
 suite "Parameterized queries":
   var db: LSMTree
   var ctx: qexec.ExecutionContext
+  var tmpDir: string
+  var paramInitialized = false
 
   setup:
-    db = newLSMTree("")
-    ctx = qexec.newExecutionContext(db)
-    discard qexec.executeQuery(ctx, parse("CREATE TABLE users (id INT, name TEXT, age INT)"))
-    discard qexec.executeQuery(ctx, parse("INSERT INTO users (id, name, age) VALUES (1, 'Alice', 30)"))
-    discard qexec.executeQuery(ctx, parse("INSERT INTO users (id, name, age) VALUES (2, 'Bob', 25)"))
+    if not paramInitialized:
+      tmpDir = getTempDir() / "baradb_param_test_" & $getMonoTime().ticks
+      db = newLSMTree(tmpDir)
+      ctx = qexec.newExecutionContext(db)
+      discard qexec.executeQuery(ctx, parse("CREATE TABLE users (id INT, name TEXT, age INT, active BOOLEAN)"))
+      discard qexec.executeQuery(ctx, parse("INSERT INTO users (id, name, age, active) VALUES (1, 'Alice', 30, true)"))
+      discard qexec.executeQuery(ctx, parse("INSERT INTO users (id, name, age, active) VALUES (2, 'Bob', 25, false)"))
+      paramInitialized = true
 
   test "SELECT with placeholder params":
     let sql = "SELECT * FROM users WHERE id = ?"
@@ -2583,6 +2655,34 @@ suite "Parameterized queries":
     check r.success
     check r.rows.len >= 1
 
+  test "JSON contains @>":
+    discard qexec.executeQuery(ctx, parse("CREATE TABLE IF NOT EXISTS jsontest2 (id INT PRIMARY KEY, data JSON)"))
+    discard qexec.executeQuery(ctx, parse("INSERT INTO jsontest2 (id, data) VALUES (1, '{\"name\": \"Alice\", \"age\": 30}')"))
+    let r = qexec.executeQuery(ctx, parse("SELECT id FROM jsontest2 WHERE data @> '{\"name\": \"Alice\"}'"))
+    check r.success
+    check r.rows.len == 1
+    check r.rows[0]["id"] == "1"
+
+  test "JSON contained by <@":
+    let r = qexec.executeQuery(ctx, parse("SELECT id FROM jsontest2 WHERE '{\"name\": \"Alice\"}' <@ data"))
+    check r.success
+    check r.rows.len == 1
+
+  test "JSON has key json_has_key":
+    let r = qexec.executeQuery(ctx, parse("SELECT id FROM jsontest2 WHERE json_has_key(data, 'name') = 'true'"))
+    check r.success
+    check r.rows.len == 1
+
+  test "JSON has any key ?|":
+    let r = qexec.executeQuery(ctx, parse("SELECT id FROM jsontest2 WHERE data ?| '[\"name\", \"missing\"]'"))
+    check r.success
+    check r.rows.len == 1
+
+  test "JSON has all keys ?&":
+    let r = qexec.executeQuery(ctx, parse("SELECT id FROM jsontest2 WHERE data ?& '[\"name\", \"age\"]'"))
+    check r.success
+    check r.rows.len == 1
+
   test "FTS match operator @@ parse":
     let ast = parse("SELECT * FROM docs WHERE content @@ 'hello'")
     check ast.stmts[0].kind == nkSelect
@@ -2630,9 +2730,11 @@ suite "Parameterized queries":
 suite "Window Functions":
   var db: LSMTree
   var ctx: qexec.ExecutionContext
+  var tmpDir: string
 
   setup:
-    db = newLSMTree("")
+    tmpDir = getTempDir() / "baradb_window_test_" & $getMonoTime().ticks
+    db = newLSMTree(tmpDir)
     ctx = qexec.newExecutionContext(db)
     discard qexec.executeQuery(ctx, parse("CREATE TABLE employees (id INT, name TEXT, department TEXT, salary INT)"))
     discard qexec.executeQuery(ctx, parse("INSERT INTO employees (id, name, department, salary) VALUES (1, 'Alice', 'Engineering', 90000)"))
@@ -2641,6 +2743,9 @@ suite "Window Functions":
     discard qexec.executeQuery(ctx, parse("INSERT INTO employees (id, name, department, salary) VALUES (4, 'Diana', 'Sales', 75000)"))
     discard qexec.executeQuery(ctx, parse("INSERT INTO employees (id, name, department, salary) VALUES (5, 'Eve', 'Engineering', 95000)"))
 
+  teardown:
+    removeDir(tmpDir)
+
   test "ROW_NUMBER with PARTITION BY and ORDER BY":
     let r = qexec.executeQuery(ctx, parse("SELECT name, department, ROW_NUMBER() OVER (PARTITION BY department ORDER BY salary DESC) AS rn FROM employees"))
     check r.success
@@ -2692,12 +2797,38 @@ suite "Window Functions":
     for row in r.rows:
       check row["bucket"] in @["1", "2"]
 
+  test "FIRST_VALUE with frame":
+    let r = qexec.executeQuery(ctx, parse("SELECT name, salary, FIRST_VALUE(salary) OVER (ORDER BY salary ROWS BETWEEN 1 PRECEDING AND CURRENT ROW) AS first_sal FROM employees"))
+    check r.success
+    check r.rows.len == 5
+    for row in r.rows:
+      if row["name"] == "Charlie":
+        check row["first_sal"] == "70000"
+      if row["name"] == "Diana":
+        check row["first_sal"] == "70000"
+      if row["name"] == "Bob":
+        check row["first_sal"] == "75000"
+
+  test "LAST_VALUE with frame":
+    let r = qexec.executeQuery(ctx, parse("SELECT name, salary, LAST_VALUE(salary) OVER (ORDER BY salary ROWS BETWEEN CURRENT ROW AND 1 FOLLOWING) AS last_sal FROM employees"))
+    check r.success
+    check r.rows.len == 5
+    for row in r.rows:
+      if row["name"] == "Charlie":
+        check row["last_sal"] == "75000"
+      if row["name"] == "Diana":
+        check row["last_sal"] == "80000"
+      if row["name"] == "Bob":
+        check row["last_sal"] == "90000"
+
 suite "GROUP BY Aggregates":
   var db: LSMTree
   var ctx: qexec.ExecutionContext
+  var tmpDir: string
 
   setup:
-    db = newLSMTree("")
+    tmpDir = getTempDir() / "baradb_group_test_" & $getMonoTime().ticks
+    db = newLSMTree(tmpDir)
     ctx = qexec.newExecutionContext(db)
     discard qexec.executeQuery(ctx, parse("CREATE TABLE sales (id INT, dept TEXT, amount INT)"))
     discard qexec.executeQuery(ctx, parse("INSERT INTO sales (id, dept, amount) VALUES (1, 'A', 100)"))
@@ -2706,6 +2837,9 @@ suite "GROUP BY Aggregates":
     discard qexec.executeQuery(ctx, parse("INSERT INTO sales (id, dept, amount) VALUES (4, 'B', 50)"))
     discard qexec.executeQuery(ctx, parse("INSERT INTO sales (id, dept, amount) VALUES (5, 'C', 300)"))
 
+  teardown:
+    removeDir(tmpDir)
+
   test "GROUP BY with COUNT(*)":
     let r = qexec.executeQuery(ctx, parse("SELECT dept, COUNT(*) AS cnt FROM sales GROUP BY dept"))
     check r.success
@@ -2808,6 +2942,26 @@ suite "GROUP BY Aggregates":
     check r.success
     check r.rows.len == 4  # one row per employee
 
+  test "CUBE execution":
+    let r = qexec.executeQuery(ctx, parse("SELECT dept, SUM(amount) AS total FROM sales GROUP BY CUBE (dept)"))
+    check r.success
+    # 3 dept groups + 1 grand total = 4 rows
+    check r.rows.len == 4
+
+  test "GROUPING SETS execution":
+    let r = qexec.executeQuery(ctx, parse("SELECT dept, SUM(amount) AS total FROM sales GROUP BY GROUPING SETS ((dept), ())"))
+    check r.success
+    # 3 dept groups + 1 grand total = 4 rows
+    check r.rows.len == 4
+
+  test "UNPIVOT execution":
+    discard qexec.executeQuery(ctx, parse("CREATE TABLE pivoted (name TEXT, eng_salary INT, sales_salary INT)"))
+    discard qexec.executeQuery(ctx, parse("INSERT INTO pivoted (name, eng_salary, sales_salary) VALUES ('Alice', 90000, 0)"))
+    discard qexec.executeQuery(ctx, parse("INSERT INTO pivoted (name, eng_salary, sales_salary) VALUES ('Bob', 0, 70000)"))
+    let r = qexec.executeQuery(ctx, parse("SELECT * FROM pivoted UNPIVOT (salary FOR dept IN (eng_salary, sales_salary))"))
+    check r.success
+    check r.rows.len == 4
+
 # JOIN tests
 include "join_tests"