[英]custom paging using ROW_NUMBER() in sql for asp.net gridview
我正在尝试使用sql中的ROW_NUMBER()在asp.net中为gridview实现自定义分页。 下面的(经典)查询效果很好,但是它的性能不是很好,因为我必须将整个表复制到新表中,然后从新表中选择20条记录。 有时甚至无需分页就可以更好地工作,而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。 如何改善以下查询? 您有什么建议? 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,但是如何呢?
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
您真的不需要使用临时表来进行如此简单的操作,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
我不确定这是否可以解决您的性能问题,可以使用子查询代替临时表:
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;
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
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