DECLARE @keys nvarchar(200)
DECLARE @pageindex int
DECLARE @pagesize int
DECLARE @classid int

set @keys = ''
set @pageindex = 1;
set @pagesize = 20;
set @classid = 17;

with temptbl as (
    select ROW_NUMBER() OVER (ORDER BY B.iid desc)AS Row, A.className,B.*  
    from dl_PicClass A inner join  dl_PicFile B on a.iid = b.classid 
    where (@keys = '' or A.className like '%'+@keys+'%' or B.fName like '%'+@keys+'%'  )
    and (@classid<=0 or B.classid = @classid)
)
SELECT * FROM temptbl where Row between (@pageindex-1)*@pagesize+1 and (@pageindex-1)*@pagesize+@pagesize;

select COUNT(1)
    from dl_PicClass A inner join  dl_PicFile B on a.iid = b.classid 
    where (@keys = '' or A.className like '%'+@keys+'%' or B.fName like '%'+@keys+'%'  )
    and (@classid<=0 or B.classid = @classid)