Mysql 聚集函數和分組

Mysql 聚集函數有5個：

1、COUNT() 記錄個數

2、MAX() 最大值

3、MIN() 最小值

4、AVG()平均值

5、SUM() 求和

聚集函數常常和分組一起工作。

1、創建分組

     select name, max(age) from stu group by name;

2、過濾分組

     select name, max(age) from stu group by name having min(age) >10;

3、分組排序

     select name, max(age) from stu group by name having min(age) >10 order by max(age) asc;

     select name, max(age) from stu group by name having min(age) >10 order by max(age) desc limit 1,5;