每次用户访问页面时,我都会使用logtime对其进行登录,现在我想查找ID为“MyID”的用户的最新不同100页。对SQL性能的建议
我使用以下SQL来选择不同的记录,但性能不佳。任何人都可以有任何改善建议吗?
Select distinct Top 100 Url,PageName,
(select top 1 inner_pa.LogTime from PageActivity inner_pa with(nolock)
where inner_pa.Key = pa.Key
and inner_pa.UserID='MyID'
order by inner_pa.LogTime Desc) as LogTime
From PageActivity pa WITH(NOLOCK)
Where pa.UserId='MyID'
Order By LogTime DESC
==================================
表模式是如下
ID int(PK)
PageName varchar
Key varchar
Username varchar
Url text
LogTime datetime
所以,如果我有以下记录
ID PageName Key UserName Url LogTime
1 PageA post MyID PageA.html 2011/1/1/12:10:10
2 PageA post MyID PageA.html 2011/1/1/12:10:15
3 PageB post MyID PageB.html 2011/1/1/12:10:30
4 PageB post MyID PageB.html 2011/1/1/12:10:45
4 PageB post OtherID PageB.html 2011/1/1/12:10:48
我从查询想要的结果将是
PageName Url
PageA PageA.html
PageB PageB.html
============================================= ========================
事情变了。现在,网址将结合不同表中的字段,如
Select distinct Top 100 pa.PageName,
pu.URL + '=' + pa.Key as URL,
(select top 1 inner_pa.LogTime from PageActivity inner_pa with(nolock)
where inner_pa.Key = pa.Key
and inner_pa.UserID='MyID'
order by inner_pa.LogTime Desc) as LogTime
From PageActivity pa WITH(NOLOCK)
Join PageUrl pu on pa.UrlID = pu.ID
Where pa.UserId='MyID'
Order By LogTime DESC
任何想法?
屏幕截图请..或发布两个表及其FK的等 – 2011-03-03 11:05:27
您好我已经添加了表模式,例如数据和查询所需的结果。请指教。 – Charlie 2011-03-17 09:46:54