CREATE DATABASE db_name;

CREATE USER username WITH PASSWORD 'password';

CREATE TABLE table_name (
    column1 datatype,
    column2 datatype,
    ...
    constraint_name constraint_type (column_list)
);

-- 示例
CREATE TABLE employees (
    id INT PRIMARY KEY,
    name VARCHAR(50) NOT NULL,
    department VARCHAR(50),
    salary DECIMAL(10, 2)
);

ALTER TABLE table_name
ADD COLUMN new_column datatype;

-- 或

ALTER TABLE table_name
DROP COLUMN column_to_remove;

CREATE INDEX idx_name ON table_name (column_to_index);

INSERT INTO table_name (column1, column2, ...)
VALUES (value1, value2, ...);

-- 示例
INSERT INTO employees (id, name, department, salary)
VALUES (1, 'John Doe', 'Sales', 50000.00);

UPDATE table_name
SET column1 = new_value1, column2 = new_value2, ...
WHERE condition;

-- 示例
UPDATE employees
SET salary = salary * 1.1
WHERE department = 'Sales';

DELETE FROM table_name
WHERE condition;

-- 示例
DELETE FROM employees
WHERE department = 'Marketing';

SELECT column1, column2, ...
FROM table_name
WHERE condition
ORDER BY column1 [ASC|DESC]
LIMIT limit_count OFFSET offset_count;

-- 示例
SELECT id, name, salary
FROM employees
WHERE department = 'IT'
ORDER BY salary DESC
LIMIT 10;

SELECT COUNT(*), AVG(salary), MAX(salary), MIN(salary)
FROM employees;

SELECT e.id, e.name, d.department_name
FROM employees e
JOIN departments d ON e.department = d.department_id;

GRANT privilege_list ON object TO user;

-- 示例
GRANT SELECT, INSERT, UPDATE ON employees TO user1;

REVOKE privilege_list ON object FROM user;

BEGIN TRANSACTION;

-- 执行一系列操作...

COMMIT; -- 提交事务，永久保存更改

-- 或

ROLLBACK; -- 回滚事务，取消所有未提交的更改

ALTER SESSION SET parameter_name = value;

-- 示例
ALTER SESSION SET search_path = 'public, my_schema';

-- 查看数据库状态
SELECT pg_stat_activity FROM pg_catalog.pg_stat_activity;

-- 重启数据库
SELECT pg_ctl restart;