Question

我正在尝试使用sql中的ROW_NUMBER（）在asp.net中实现gridview的自定义分页。下面的（经典）查询效果很好，但是它的性能不是那么好，因为我必须将整个表复制到一个新表，然后从新表中选择20个记录。如果没有分页，有时甚至可以更好地工作，只需一次检索所有记录。我试图在where子句中使用ROW_NUMBER（），但是sql不允许我这样做。如何改进下面的查询？你的建议是什么？我想我需要找到一种方法来消除将整个数据集复制到新表的过程，但是如何？

SELECT PostId, Message, (ROW_NUMBER() OVER (ORDER BY LastUpdateDateTime DESC)) as Row   

INTO #Results   
FROM   Posts
WHERE  Posts.TimePointId=@TimePointId AND IsFixed=0 

ORDER BY LastUpdateDateTime DESC

-----------------------------------------------------


SELECT * FROM #Results
WHERE Row BETWEEN(@PageIndex -1) * @PageSize + 1 AND(((@PageIndex -1) * @PageSize + 1) + @PageSize) - 1

DROP TABLE #Results

Answer 1

你真的不需要使用临时表来进行这样简单的操作，只需使用子查询或CTE。

使用子查询

SELECT * 
FROM (
SELECT PostId, Message, (ROW_NUMBER() OVER (ORDER BY LastUpdateDateTime DESC)) as Row    
FROM   Posts
WHERE  Posts.TimePointId=@TimePointId AND IsFixed=0 
) Sub
WHERE Row BETWEEN(@PageIndex -1) * @PageSize + 1 
AND(((@PageIndex -1) * @PageSize + 1) + @PageSize) - 1

使用CTE

;WITH CTE
AS
 (
    SELECT PostId, Message, (ROW_NUMBER() OVER (ORDER BY LastUpdateDateTime DESC)) as Row     
    FROM   Posts
    WHERE  Posts.TimePointId=@TimePointId AND IsFixed=0 
 )
SELECT * 
FROM CTE
WHERE Row BETWEEN(@PageIndex -1) * @PageSize + 1 
AND(((@PageIndex -1) * @PageSize + 1) + @PageSize) - 1

Answer 2

我不确定这是否会解决您的性能问题，您可以使用子查询而不是临时表：

SELECT p.*
FROM (SELECT PostId, Message, (ROW_NUMBER() OVER (ORDER BY LastUpdateDateTime DESC)) as Row    
      FROM   Posts
      WHERE  Posts.TimePointId=@TimePointId AND IsFixed=0 
     ) p
WHERE Row BETWEEN(@PageIndex -1) * @PageSize + 1 AND(((@PageIndex -1) * @PageSize + 1) + @PageSize) - 1;

Answer 3

您可以使用CTE;

;With CTE as
(
SELECT PostId, Message, (ROW_NUMBER() OVER (ORDER BY LastUpdateDateTime DESC)) as Row   
FROM   Posts
WHERE  Posts.TimePointId=@TimePointId AND IsFixed=0 

ORDER BY LastUpdateDateTime DESC

)SELECT Row,* FROM CTE
WHERE Row BETWEEN(@PageIndex -1) * @PageSize + 1 AND(((@PageIndex -1) * @PageSize + 1) + @PageSize) - 1

在asp.net gridview的sql中使用ROW_NUMBER（）进行自定义分页

3 个答案: