mysql查询语句两个表

-- 创建示例表
CREATE TABLE employees (
    id INT PRIMARY KEY,
    name VARCHAR(100),
    department_id INT
);

CREATE TABLE departments (
    id INT PRIMARY KEY,
    name VARCHAR(100)
);

-- 插入示例数据
INSERT INTO employees (id, name, department_id) VALUES (1, 'Alice', 1);
INSERT INTO employees (id, name, department_id) VALUES (2, 'Bob', 2);
INSERT INTO departments (id, name) VALUES (1, 'HR');
INSERT INTO departments (id, name) VALUES (2, 'Engineering');

-- 内连接查询
SELECT e.name AS employee_name, d.name AS department_name
FROM employees e
INNER JOIN departments d ON e.department_id = d.id;

-- 左外连接查询
SELECT e.name AS employee_name, d.name AS department_name
FROM employees e
LEFT OUTER JOIN departments d ON e.department_id = d.id;

-- 右外连接查询
SELECT e.name AS employee_name, d.name AS department_name
FROM employees e
RIGHT OUTER JOIN departments d ON e.department_id = d.id;