Mysql 单表查询各班级总分前三名

select class,total,name from (select *,ywsc+sxsc as total from st ORDER BY total DESC) b

where

not EXISTS(select * from (select *,ywsc+sxsc as total from st ORDER BY total DESC) c where c.class=b.class and b.total <c.total GROUP BY c.class HAVING COUNT(*)>2 )

ORDER BY b.class,b.total DESC

select b.obj_id, a.avg(score) avgScore from study a left join task b on a.task_id = a.id where a.class_id = ## group by b.obj_id order by a.avg(score)

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