sql - SQL从两个表中的查询匹配条件中删除？

Question

此查询将删除所有行，而我只想删除measureid两个表中匹配的行，如下所示：

delete from temp1 
where exists (select t1.* 
              from temp1 t1, temp2 t2 
              where t2.measureid = t1.measureid)

我必须改变什么？

score 3 · Accepted Answer

我想你不想用exists我想你想用in

delete from temp1 where measureid in 
    (select t1.measureid from temp1 t1, temp2 t2 where t2.measureid = t1.measureid);

或者更好

delete from temp1 where measureid in 
    (select measureid from temp2);

score 1 · Accepted Answer

那是因为

select t1.* from temp1 t1, temp2 t2 where t2.measureid = t1.measureid

总是返回行。你可能想要的是

delete from temp1 t1 where exists (select t2.* from temp2 t2 where t2.measureid = t1.measureid)

2 回答 2