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1.创建数据库：create DATABASE 数据库名 CHARACTER set utf8;
不用utf8,在输入中文时会乱码。
2.查看数据库：show create database 数据库名。
3.删除数据库：drop database 数据库名;
4.进入数据库：use 数据库名;
5.查看表结构：desc 表名;
6.查看创建表结构：show create table 表名;
7.删除表：drop table 表名;
8.添加字段：alter table student add 字段 类型(长度)；
9.删除字段：alter table student drop 字段;
10:修改字段：alter table student MODIFY 字段 类型(长度)；
11:新增数据一条:INSERT into student values (字段值,字段值,，，，);
12:多条:INSERT into student values (字段值,字段值,，，，),(字段值,字段值,，，，),(字段值,字段值,，，，);
13:修改一条数据中的一个字段:update 表名 set 字段=新值 where 条件;
14.修改一条数据中的多个字段:update 表名 set 字段=新值,字段=新值 where 条件;
15.删除一条数据:delete from student where 条件;
16.删除表中全部数据:delete from student ;
17.查询全部信息：select * from student;
18.查询一条信息：select * from student where sname = ‘’;
19.条件查询：select * from student where sid = 1 or sid = 3;
select * from student where sid in(1,3);
20.条件查询：select * from student where sscore > 50 and sscore < 90;
select * from student where sscore BETWEEN 50 and 90;
21:模糊查询：select * from student where sname like ‘哈%’;
select * from student where sname like ‘%哈’;
select * from student where sname like ‘%哈%’;
22.排序(倒序)：select * from student ORDER BY sscore desc;
23.分页：select * from student limit 1,2;
24.分组：select count(*),ssex from student GROUP BY ssex HAVING 条件
25.聚合数据：count()/avg()/min()/max()/sum()
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