mysql 数据的增删改例题

向表中插入数据，使用UNION和子查询

INSERT INTO users
VALUES(1,'a'),
VALUES(2,'b'),
VALUES(3,'c');

或

INSERT INTO users
SELECT 1,'a' UNION
SELECT 2,'b' UNION
SELECT 3,'c' ;

将3号员工的last_name 修改为'drelexer'

UPDATE my_employees SET last_name ='drelexer' WHERE id =3;

将所有工资少于900的员工的工资修改为1000

UPDATE my_employees SET salary=9000 WHERE salary<900;

将userid为Bbiri的USER表和my_employees表的记录全部删除

DELETE u,m
FROM USER u
INNER JOIN my_employees m
ON u.userid=m.userid
WHERE u.userid='Bbiri';