先聚合再连接

string SQL = @"select isnull(i.IntegralSum,0.0)as IntegralSum,a.AccountSum,u.UserLave,u.AddTime from Bst_User u 

left join  (select UserId,sum(cast(IntegralCount as numeric(10,2))) as IntegralSum 

from Bst_Integral where IsOver=0 group by UserId) i 

on i.UserId=u.UserId 

inner join (select UserId,sum(cast(YourCount as numeric(10,2))) as AccountSum from Bst_UserAccount group by UserId) a

on a.UserId=u.UserId where u.UserName='"+ Session["User"].ToString() + "'";

string SQL = @"

select * from (select top 1 Id, Title,ArtPic from

(

select top 1 Id, Title,ArtPic from  Ec_Art where IsCheck=1  and  ArtPic<>'' and IsTop=1 and  NodeId=25

union 

select  0,'暂无新闻','images/tp.gif' 

)aa  order by Id desc

union all 

select top 1 Id, Title,ArtPic from 

(

select top 1  Id, Title,ArtPic from  Ec_Art where IsCheck=1  and  ArtPic<>'' and IsTop=1 and  NodeId=28

union all 

select  0,'暂无新闻','images/tp.gif' 

)bb  order by Id desc

union all 

select top 1 Id, Title,ArtPic from 

(

select top 1  Id, Title,ArtPic from  Ec_Art where IsCheck=1  and  ArtPic<>'' and IsTop=1 and  NodeId=30

union all 

select  0,'暂无新闻','images/tp.gif' 

)cc  order by Id desc

union all 

select top 1 Id, Title,ArtPic from 

(

select top 1  Id, Title,ArtPic from  Ec_Art where IsCheck=1  and  ArtPic<>'' and IsTop=1 and  NodeId=36

union all 

select  0,'暂无新闻','images/tp.gif' 

)dd  order by Id desc

union all 

select top 1 Id, Title,ArtPic from 

(

select top 1  Id, Title,ArtPic from  Ec_Art where IsCheck=1  and  ArtPic<>'' and IsTop=1 and  NodeId=38

union all 

select  0,'暂无新闻','images/tp.gif' 

)ee  order by Id desc

union all 

select top 1 Id, Title,ArtPic from 

(

select top 1  Id, Title,ArtPic from  Ec_Art where IsCheck=1  and  ArtPic<>'' and IsTop=1 and  NodeId=42

union all 

select  0,'暂无新闻','images/tp.gif' 

)ff  order by Id desc

union all 

select top 1 Id, Title,ArtPic from 

(

select top 1  Id, Title,ArtPic from  Ec_Art where IsCheck=1  and  ArtPic<>'' and IsTop=1 and  NodeId=34

union all 

select  0,'暂无新闻','images/tp.gif' 

)gg  order by Id desc

union all 

select top 1 Id, Title,ArtPic from 

(

select top 1  Id, Title,ArtPic from  Ec_Art where IsCheck=1  and  ArtPic<>'' and IsTop=1 and  NodeId=31

union all 

select  0,'暂无新闻','images/tp.gif' 

)hh  order by Id desc)

ddd";