sql server 分页问题

 set @sql = ' select  a.* 
from(select row_number() over ( order by ' + @PageOrderBy + ' ' + @PageOrder + ') Num, a.*
from( select  * from #SpcBuilderAnalysis
) a
) a
where '+convert(varchar,@PageSize) +' < 0 or (a.num >  '
    + convert(varchar, (@PageNo-1)*@PageSize )
    + ' and a.num <= '+ convert(varchar, @PageNo*@PageSize) +')' 
    exec(@sql)