Mysql教程：（六）修改语句、、删除语句、字符查询like

1、修改语句

update 表名 set  where 条件

mysql> update student set birth=1988,department='中文系' where id=901 and name='张老大';

把张老大的出生日期修改为1988，院系修改成中文系

mysql> update student set birth=birth-5；

2、删除语句

删除901同学的，学生信息

mysql> delete from student where id=901;

删除湖南籍学生的信息

mysql> delete from student where address like "湖南%";

清空学生表信息

mysql> delete from student;

3、字符查询like

查询地址为北京的学生信息

mysql> select * from student where address like '北京%';

查询地址为北京市昌平区的学生信息

mysql> select * from student where address like '%北京%平%';

查询湖南籍学生的成绩信息；

mysql> select * from score where stu_id in (select id from student where address like '湖南%');

4、作业

1，把张三的计算机成绩修改成60分

update score set grade=60 where stu_id in(select id from student where name='张三')and c_name='计算机';

2，把计算机科目的分数降低5分

update score set grade=grade-5 where c_name='计算机';

3，把湖南省学生计算机分数提高5分

 update score set grade=grade+5 where c_name='计算机'and stu_id in(select id from student where address like '湖南%');

4，把学号为904的学生，计算机成绩改为85

 update score set grade=85 where c_name='计算机' and stu_id=904;

5，删除904学生的成绩

delete from score where stu_id=904;

6，删除湖南籍贯学生的成绩

 delete from score where stu_id in(select id from student where address like '湖南%'); 

7，删除王姓与张姓同学英语成绩

delete from score where stu_id in (select id from student where name like '王%'or name like '张%') and c_name='英语';

8，删除年纪大于30的学生的计算机成绩

 delete from score where stu_id in (select id from student where 2016-birth>30);