select p.name,sum(p.cost),p.typyid from Plan_info p left join dept d on p.planid = d.planid group by p.type 这是我写的语句，愿意是一个计划表连接一个部门表，现需要显示计划名称并sum费用。单统计计划表时没有问题。关联上部门表后就出现了很多重复记录，sum的数据就不准了，求正确写法，感谢！！SQL code: select p.name,sum(DISTINCT p.cost),p.typyid from Plan_info p left join dept d on p.planid = d.planid group by p.type
最好是先统计再子查询,一定不会出错 SQL code: select p.name,sum(DISTINCT ISNULL(p.cost,0)),p.typyid from Plan_info p left join dept d on p.planid = d.planid group by p.type
select p.name,sum(p.cost),p.typyid from Plan_info p left join dept d on p.planid = d.planid group by p.name,p.typyid SQL code: select p.name,p.cost,p.typyid from ( select sum(cost) cost,typyid,planid,name from Plan_info group by typyid,planid,name ) p left join dept d on p.planid = d.planid
