mysql 怎么给表取别名

SELECT t1.column1, t2.column2
FROM table1 t1
JOIN table2 t2 ON t1.id = t2.id;

SELECT t1.column1, t2.column2
FROM table1 t1
JOIN table2 t2 ON t1.id = t2.id;

SELECT t1.column1, subquery_result.column2
FROM table1 t1
JOIN (SELECT column2 FROM table2 WHERE condition) subquery_result ON t1.id = subquery_result.id;

-- 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),
(2, 'Bob', 2),
(3, 'Charlie', 1);

INSERT INTO departments (id, name) VALUES
(1, 'HR'),
(2, 'Engineering');

-- 使用别名进行查询
SELECT e.name AS employee_name, d.name AS department_name
FROM employees e
JOIN departments d ON e.department_id = d.id;