INSERT INTO table [(column [, column...])]
VALUES (value [, value...]);
1.向emp表中插入一行数据 //字符和日期需要使用单引号
insert into emp(empno,ename,sal) values(7380,'allen_walker',3500);
UPDATE table
SET column = value [, column = value, ...]
[WHERE condition];
1.将empno为7390的员工的工资调整为3500
update emp set sal=3500 where empno=7390;
2.将empno为7390的员工的工资调整为和empno为7391号员工的工资一致
update emp set sal=(select sal from emp where empno=7391) where empno=7390;
DELETE [FROM] table
[WHERE condition];
1.删除员工编号为7390的员工信息
delete from emp where empno=7390;