9.3 KiB
9.3 KiB
BaraQL - 查询语言参考
BaraQL 是一个与 SQL 兼容的查询语言，包含图、向量和文档操作的扩展。
数据类型
| 类型 | 描述 | 示例 |
|---|---|---|
null |
空值 | null |
bool |
布尔值 | true, false |
int8 |
8 位有符号整数 | 127 |
int16 |
16 位有符号整数 | 32767 |
int32 |
32 位有符号整数 | 2147483647 |
int64 |
64 位有符号整数 | 9223372036854775807 |
float32 |
32 位浮点数 | 3.14 |
float64 |
64 位浮点数 | 3.14159265359 |
str |
UTF-8 字符串 | 'hello' |
bytes |
原始字节 | 0xDEADBEEF |
array<T> |
同构数组 | [1, 2, 3] |
vector |
Float32 向量 | [0.1, 0.2, 0.3] |
object |
键值对象 | {"a": 1} |
datetime |
ISO 8601 时间戳 | '2025-01-15T10:30:00Z' |
uuid |
UUID v4 | '550e8400-e29b-41d4-a716-446655440000' |
json |
JSON 文档 | {"key": "value"} |
jsonb |
二进制 JSON（已验证） | {"key": "value"} |
基本查询
SELECT
-- 所有列
SELECT * FROM users;
-- 特定列
SELECT name, age FROM users;
-- 别名
SELECT name AS full_name, age AS years FROM users;
-- DISTINCT
SELECT DISTINCT department FROM employees;
-- LIMIT 和 OFFSET
SELECT * FROM users LIMIT 10 OFFSET 20;
WHERE
-- 比较运算符
SELECT * FROM users WHERE age > 18;
SELECT * FROM users WHERE age >= 18 AND age <= 65;
SELECT * FROM users WHERE name = 'Alice';
SELECT * FROM users WHERE name != 'Bob';
-- 范围
SELECT * FROM users WHERE age BETWEEN 18 AND 65;
-- 集合成员
SELECT * FROM users WHERE department IN ('Engineering', 'Sales');
-- 模式匹配
SELECT * FROM users WHERE name LIKE 'A%';
SELECT * FROM users WHERE name ILIKE 'alice'; -- 不区分大小写
-- NULL 检查
SELECT * FROM users WHERE email IS NOT NULL;
-- 逻辑运算符
SELECT * FROM users WHERE age > 18 AND (department = 'Engineering' OR department = 'Sales');
ORDER BY
-- 升序（默认）
SELECT * FROM users ORDER BY age;
-- 降序
SELECT * FROM users ORDER BY age DESC;
-- 多列
SELECT * FROM users ORDER BY department ASC, age DESC;
INSERT
-- 单行
INSERT users { name := 'Alice', age := 30 };
-- 显式类型
INSERT User { name := 'Alice', age := 30 };
-- 多行
INSERT users {
{ name := 'Alice', age := 30 },
{ name := 'Bob', age := 25 }
};
UPDATE
-- 更新所有行
UPDATE users SET status = 'active';
-- 条件更新
UPDATE users SET age = 31 WHERE name = 'Alice';
-- 更新多列
UPDATE users SET age = 32, status = 'premium' WHERE name = 'Alice';
DELETE
-- 删除所有行
DELETE FROM users;
-- 条件删除
DELETE FROM users WHERE age < 18;
聚合和分组
聚合函数
| 函数 | 描述 |
|---|---|
count(*) |
计算所有行 |
count(column) |
计算非 NULL 值 |
sum(column) |
值之和 |
avg(column) |
平均值 |
min(column) |
最小值 |
max(column) |
最大值 |
stddev(column) |
标准差 |
variance(column) |
方差 |
GROUP BY
SELECT department, count(*) as emp_count, avg(salary) as avg_salary
FROM employees
GROUP BY department;
-- 带 HAVING
SELECT department, count(*) as emp_count
FROM employees
GROUP BY department
HAVING count(*) > 5;
-- 多重分组
SELECT department, role, count(*), avg(salary)
FROM employees
GROUP BY department, role;
JOIN
-- INNER JOIN
SELECT u.name, o.total
FROM users u
INNER JOIN orders o ON u.id = o.user_id;
-- LEFT JOIN
SELECT u.name, o.total
FROM users u
LEFT JOIN orders o ON u.id = o.user_id;
-- RIGHT JOIN
SELECT u.name, o.total
FROM users u
RIGHT JOIN orders o ON u.id = o.user_id;
-- FULL JOIN
SELECT u.name, o.total
FROM users u
FULL JOIN orders o ON u.id = o.user_id;
-- CROSS JOIN
SELECT u.name, p.name
FROM users u
CROSS JOIN products p;
-- 多重 JOIN
SELECT u.name, o.id, p.name
FROM orders o
JOIN users u ON o.user_id = u.id
JOIN products p ON o.product_id = p.id;
-- Self JOIN
SELECT e.name, m.name as manager
FROM employees e
JOIN employees m ON e.manager_id = m.id;
CTE（公用表表达式）
-- 单个 CTE
WITH active_users AS (
SELECT * FROM users WHERE active = true
)
SELECT * FROM active_users;
-- 多个 CTE
WITH
recent AS (
SELECT * FROM orders WHERE date > '2025-01-01'
),
totals AS (
SELECT user_id, sum(amount) as total FROM recent GROUP BY user_id
)
SELECT u.name, t.total
FROM users u
JOIN totals t ON u.id = t.user_id;
-- 递归 CTE
WITH RECURSIVE subordinates AS (
SELECT id, name, manager_id FROM employees WHERE name = 'CEO'
UNION ALL
SELECT e.id, e.name, e.manager_id
FROM employees e
JOIN subordinates s ON e.manager_id = s.id
)
SELECT * FROM subordinates;
子查询
-- SELECT 中的子查询
SELECT name, (SELECT count(*) FROM orders WHERE user_id = u.id) as order_count
FROM users u;
-- FROM 中的子查询
SELECT * FROM (SELECT id, name FROM users WHERE active = true) AS active;
-- WHERE 中的子查询 (IN)
SELECT name FROM users WHERE id IN (SELECT user_id FROM orders);
-- WHERE 中的子查询 (EXISTS)
SELECT name FROM users WHERE EXISTS (SELECT 1 FROM orders WHERE orders.user_id = users.id);
-- 相关子查询
SELECT name FROM users u
WHERE age > (SELECT avg(age) FROM users WHERE department = u.department);
CASE 表达式
SELECT name,
CASE
WHEN age < 13 THEN 'child'
WHEN age < 20 THEN 'teenager'
WHEN age < 65 THEN 'adult'
ELSE 'senior'
END AS category
FROM users;
-- 简单 CASE
SELECT name,
CASE department
WHEN 'Engineering' THEN 'Tech'
WHEN 'Sales' THEN 'Revenue'
ELSE 'Other'
END AS division
FROM employees;
集合运算
-- UNION（去重）
SELECT name FROM customers
UNION
SELECT name FROM suppliers;
-- UNION ALL（保留重复）
SELECT name FROM customers
UNION ALL
SELECT name FROM suppliers;
-- INTERSECT
SELECT name FROM customers
INTERSECT
SELECT name FROM suppliers;
-- EXCEPT
SELECT name FROM customers
EXCEPT
SELECT name FROM suppliers;
模式定义
CREATE TYPE
CREATE TYPE Person {
name: str,
age: int32
};
-- 带必填字段
CREATE TYPE User {
email: str REQUIRED,
name: str,
age: int32,
created_at: datetime DEFAULT now()
};
-- 带链接
CREATE TYPE Movie {
title: str,
year: int32,
director: Person
};
-- 带计算属性
CREATE TYPE Employee {
name: str,
base_salary: float64,
bonus: float64,
total_compensation: float64 COMPUTED (base_salary + bonus)
};
继承
CREATE TYPE Animal {
name: str
};
CREATE TYPE Dog EXTENDING Animal {
breed: str
};
CREATE TYPE Cat EXTENDING Animal {
indoor: bool
};
索引
CREATE INDEX idx_users_name ON users(name);
CREATE UNIQUE INDEX idx_users_email ON users(email);
CREATE INDEX idx_users_age ON users(age) USING btree;
DROP
DROP TYPE User;
DROP INDEX idx_users_name;
向量搜索
-- 插入向量
INSERT articles {
title := 'Nim Programming',
embedding := [0.1, 0.2, 0.3, 0.4]
};
-- 相似性搜索（余弦距离）
SELECT title FROM articles
ORDER BY cosine_distance(embedding, [0.1, 0.2, 0.3, 0.4])
LIMIT 5;
-- 欧几里得距离
SELECT title FROM articles
ORDER BY l2_distance(embedding, [0.1, 0.2, 0.3, 0.4])
LIMIT 5;
-- 点积
SELECT title FROM articles
ORDER BY dot_product(embedding, [0.1, 0.2, 0.3, 0.4]) DESC
LIMIT 5;
-- 带元数据过滤
SELECT title FROM articles
WHERE category = 'tech'
ORDER BY cosine_distance(embedding, [0.1, 0.2, 0.3, 0.4])
LIMIT 5;
图模式
-- 查找 Alice 的朋友
MATCH (p:Person)-[:KNOWS]->(friend:Person)
WHERE p.name = 'Alice'
RETURN friend.name;
-- 查找最短路径
MATCH path = shortestPath((a:Person)-[:KNOWS*1..5]->(b:Person))
WHERE a.name = 'Alice' AND b.name = 'Bob'
RETURN path;
-- 查找所有关系
MATCH (p:Person)-[r]->(other)
WHERE p.name = 'Alice'
RETURN type(r), other.name;
-- 多跳
MATCH (a:Person)-[:KNOWS]->(b:Person)-[:KNOWS]->(c:Person)
WHERE a.name = 'Alice'
RETURN c.name;
-- 带聚合
MATCH (p:Person)-[:KNOWS]->(friend)
RETURN p.name, count(friend) as friend_count
ORDER BY friend_count DESC;
全文搜索
-- 基本搜索
SELECT * FROM articles
WHERE MATCH(title, body) AGAINST('database programming');
-- 带相关性评分
SELECT title, relevance()
FROM articles
WHERE MATCH(title, body) AGAINST('Nim language')
ORDER BY relevance() DESC;
-- 布尔模式
SELECT * FROM articles
WHERE MATCH(title, body) AGAINST('+Nim -Python' IN BOOLEAN MODE);
-- 模糊搜索
SELECT * FROM articles
WHERE MATCH(title) AGAINST('programing' WITH FUZZINESS 2);
事务
BEGIN;
INSERT users { name := 'Alice', age := 30 };
INSERT orders { user_id := last_insert_id(), total := 100 };
COMMIT;
-- 带保存点
BEGIN;
INSERT users { name := 'Bob', age := 25 };
SAVEPOINT sp1;
INSERT orders { user_id := last_insert_id(), total := 200 };
-- 哎呀，回滚到保存点
ROLLBACK TO sp1;
COMMIT;
用户定义函数
-- 注册 UDF
CREATE FUNCTION greet(name str) -> str {
RETURN 'Hello, ' || name || '!';
};
-- 使用
SELECT greet(name) FROM users;
-- 内置函数
SELECT abs(-5), sqrt(16), lower('HELLO'), len('test');
查询提示
-- 强制使用索引
SELECT /*+ USE_INDEX(idx_users_age) */ * FROM users WHERE age > 18;
-- 强制近似向量搜索
SELECT /*+ APPROXIMATE */ * FROM vectors
ORDER BY cosine_distance(embedding, [...])
LIMIT 10;
-- 并行执行
SELECT /*+ PARALLEL(4) */ * FROM large_table;