winfwu

导航

MYSQL基础----ORDER BY关键字 / GROUP BY关键字/ GROUP_CONCAT()函数 / COUNT()函数 / HAVING 关键字 / WITH ROLLUP关键字 / LIMIT关键字

『1』对查询结果进行排序(默认是按照Asc排序方式排序)

  select * from employee order by age;

  

『2』对查询结果进行Eesc排序

  select * from employee order by age desc;

  

『3』多次排序

  select * from employee order by d_id asc,age asc;

  

『4』order by和group_concat函数连用

  select sex,group_concat(name) from employee group by sex;

  

『5』GROUP BY 关键字与COUNT()函数连用

  select sex,count(sex) from employee group by sex;

  

『6』GROUP BY关键与HAVING一起使用

  select sex,count(sex) from employee group by sex having count(sex)>=3;

  

『7』GROUP BY 关键字与WITH ROLLUP一起使用

  select sex,count(sex) from employee group by sex with rollup; (在输出最后一行做数据统计)

  

『8』LIMIT关键字

  select * from employee limit 0,3;(从0开始一共3行)

  

 

posted on 2013-04-01 23:07  winfwu  阅读(473)  评论(0编辑  收藏  举报