表连接查询 多表查询的分类: 两个表数据 CREATE TABLE dept( id INT PRIMARY KEY AUTO_INCREMENT, NAME VARCHAR(20) ); CREATE TABLE emp( id INT PRIMARY KEY AUTO_INCREMENT, name VARCHAR(10), gender CHAR(1), salary DOUBLE, join_date DATE, dept_id INT, FOREIGN KEY (dept_id) REFERENCES dept(id) ) # 插入数据 insert into d