数据库的优化急急急急急急急急急急急急
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悬赏园豆：10
[已解决问题]
解决于 2012-11-22 11:08
select * from Gallery.Galleries where Gallery.Galleries.CreatorId in
(select Gallery.Galleries.CreatorId from Gallery.Galleries group by Gallery.Galleries.CreatorId having COUNT(Gallery.Galleries.CreatorId)>1 ) Order by CreatorId
select * from Gallery.Galleries where exists (select Gallery.Galleries.CreatorId from Gallery.Galleries group by Gallery.Galleries.CreatorId having COUNT(Gallery.Galleries.CreatorId)>1)Order by CreatorId
今天进行数据库的优化，本来以为in可以更改为exists可以提高性能但是更改过后查出来的内容不一样，求原因。
最佳答案
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第二个语句exists里面 只要有一个creatorid有多行，就会一直有值，所以第二个应该是全都查出来了。
收获园豆：10
select * from Gallery.Galleries as a where (select count(1) from Gallery.Galleries as b where b.CreatorId=a.CreatorId)>1 order by CreatorId
@飞来飞去: 不好意思我刚刚看了下查询计划，好像两个差不多。。。
