1、修改語句
update 表名 set where 條件
mysql> update student set birth=1988,department='中文系' where id=901 and name='張老大';
把張老大的出生日期修改為1988，院系修改成中文系
mysql> update student set birth=birth-5；
2、刪除語句
刪除901同學的，學生信息
mysql> delete from student where id=901;
刪除湖南籍學生的信息
mysql> delete from student where address like "湖南%";
清空學生表信息
mysql> delete from student;
3、字符查詢like
查詢地址為北京的學生信息
mysql> select * from student where address like '北京%';
查詢地址為北京市昌平區的學生信息
mysql> select * from student where address like '%北京%平%';
查詢湖南籍學生的成績信息；
mysql> select * from score where stu_id in (select id from student where address like '湖南%');
4、作業
1，把張三的計算機成績修改成60分
update score set grade=60 where stu_id in(select id from student where name='張三')and c_name='計算機';
2，把計算機科目的分數降低5分
update score set grade=grade-5 where c_name='計算機';
3，把湖南省學生計算機分數提高5分
update score set grade=grade+5 where c_name='計算機'and stu_id in(select id from student where address like '湖南%');
4，把學號為904的學生，計算機成績改為85
update score set grade=85 where c_name='計算機' and stu_id=904;
5，刪除904學生的成績
delete from score where stu_id=904;
6，刪除湖南籍貫學生的成績
delete from score where stu_id in(select id from student where address like '湖南%');
7，刪除王姓與張姓同學英語成績
delete from score where stu_id in (select id from student where name like '王%'or name like '張%') and c_name='英語';
8，刪除年紀大於30的學生的計算機成績
delete from score where stu_id in (select id from student where 2016-birth>30);