獲取索引查找而不是在分頁臨時表中進行掃描？

Question

我已經創建了一個臨時表來測試我對intindex的主鍵。

當我select * from #TmpDashboard where intindex = 1我得到了索引查找。

但是，當我應用分頁公式時，會得到索引掃描，這會導致性能問題。

Declare @Currentpage      INT = 1
      ,@Pagesize         INT = 10

select * from #TmpDashboard 
WHERE  (@Pagesize = 0 OR (intIndex BETWEEN ((@CurrentPage - 1) * @PageSize) + 1 AND (@CurrentPage * @PageSize))) --gives index scan

我如何轉換上面的公式以獲得索引查找。

Answer 1

WHERE子句中的“ OR”導致掃描，因為它使該語句不確定。 我建議設置第二組變量，您可以使用它們來簡化查詢，如下所示：

 Declare @Currentpage      INT = 1
      ,@Pagesize         INT = 10;

declare @start int = Case when @pagesizee = 0 then 0 else ((@CurrentPage - 1) * @PageSize) + 1 end
, @end int = case when @pagesize > 0 then @CurrentPage * @PageSize else (select max(intindex) from #tmpdashboard) end

select * from #TmpDashboard 
WHERE  intindex between @start and @end

Answer 2

create table #TmpDashboard (intindex int primary key)
select * from #TmpDashboard where intindex = 1
Declare @Currentpage INT, @Pagesize INT;
select  @Currentpage= 1, @Pagesize = 10;

select * from #TmpDashboard 
WHERE  intIndex BETWEEN ((@CurrentPage - 1) * @PageSize) + 1 AND (@CurrentPage * @PageSize)
drop table #TmpDashboard