分组

GROUP BY

格式：select 组函数 from 表 where 条件 group by 字段;

特别的group by 必须在where之后,order by之前

HAVING 组判断条件，它的真假决定一组数据是否返回

格式：select 组函数 from 表 where 条件 group by 字段 having 组判断条件;

select num from tb1 group by num;

select num, id from tb1 group by num, id;

select num, id from tb1 where id > 5 group by num, id order by id desc;

select num, id count(*), sum(score), max(score), min(score) from tb1 group by num, id;

select num from tb1 group by num having max(id) > 10;

————————————————

版权声明：本文为CSDN博主「holysll」的原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接及本声明。

原文链接：https://blog.csdn.net/holysll/article/details/107227402