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MySQL笔记之基本查询的应用详解_MySQL教程

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mysql密码过期了,今天遇到了连接mysql,总是连接不上去,下面有两种错误现象,有类似问题的朋友可以参考看看,或许对你有所帮助

参考表:student



多字段查询

复制代码 代码如下:www.mb5u.com

mysql> select id,name,birth from student;


所有字段查询
复制代码 代码如下:www.mb5u.com

mysql> select * from student;


where指定查询
复制代码 代码如下:www.mb5u.com

mysql> select * from student where id=901;
mysql> select * from student where id>=904;
mysql> select name from student where department='计算机系';


in指定集合查询
复制代码 代码如下:www.mb5u.com

mysql> select * from student where birth in(1988,1990);
mysql> select * from student where id in(903,906);

not in非范围查询
复制代码 代码如下:www.mb5u.com

mysql> select * from student where birth not in(1990,1998);


between and指定范围查询
复制代码 代码如下:www.mb5u.com

mysql> select * from student where birth between 1986 and 1988;


not between and不在指定范围的查询
复制代码 代码如下:www.mb5u.com

mysql> select * from student where id not between 904 and 906;


like字符串匹配查询
复制代码 代码如下:www.mb5u.com

mysql> select * from student where name like '_三';
mysql> select * from student where name like '张三';
mysql> select * from student where name like '张%';


not like不匹配查询
复制代码 代码如下:www.mb5u.com

mysql> select * from student where name not like '张%';


null查询
复制代码 代码如下:www.mb5u.com

mysql> select * from student where address is null;


and多条件查询
复制代码 代码如下:www.mb5u.com

mysql> select * from student where name like '张%' and birth>1985;
mysql> select * from student where name like '张%' and birth>1985 and id like '%3';


or多条件查询
复制代码 代码如下:www.mb5u.com

mysql> select * from student where id=905 or birth=1988;
mysql> select * from student where id=905 or birth=1988 or sex='女';

 

distinct查询结果不重复

复制代码 代码如下:www.mb5u.com

mysql> select distinct sex from student;
mysql> select distinct department from student;


order by查询结果排序
复制代码 代码如下:www.mb5u.com

mysql> select * from student order by birth;
mysql> select * from student order by birth asc;
mysql> select * from student order by birth desc;


group by分组查询
复制代码 代码如下:www.mb5u.com

mysql> select sex,group_concat(name) from student group by sex;
mysql> select sex,count(name) from student group by sex;


正则表达式查询
复制代码 代码如下:www.mb5u.com

mysql> select * from student where birth regexp '1988|1990';


limit限制查询结果数量
复制代码 代码如下:www.mb5u.com

mysql> select * from student limit 2;
mysql> select * from student limit 1,3;

 


分享:MySQL笔记之索引的使用
索引是创建在表上的,对数据库表中一列或多列的值进行排序的一种结构其作用主要在于提高查询的速度,降低数据库系统的性能开销

来源:模板无忧//所属分类:MySQL教程/更新时间:2013-05-04
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