--insert into添加数据

insert into student(sno,sname,ssex) values('','王军','男');

--提交事物

commit;

--回滚事物

--rollback;

insert into teacher1 select * from teacher;

insert into teacher1(ton,tname,prof) select ton,tname,prof from teacher;

--选择性插入两表之间

insert into teacher1 t(ton,tname,prof) select ton,tname,prof from teacher where ton='';

--修改 update

update student set sclass=''，ssex='女' where son='';

commit

--修改成绩

update score set degree=degree+1;

--将空sclass内容更改95033

update student set sclass='' where sclass is null; 

--删除 delete

delete from student where sno='';

--全表快速清空：先删表，在建表

truncate table stdent;