风叉叉

摘要： 1.在Hql中使用group by的问题(1)使用统计函数作为输出结果select sum(total),sum(totalup) from AD where aid=? and fid=? and vdatetime>=? and vdatetime<=? group by aid(2)使用统计函数作为查询约束条件select uid from MM group by uid having count(*)>? and min(m_date)<?(3)使用group by 时有关约束条件的问题如果约束条件是单个字段,则必须用where,并且where要放在group 阅读全文