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SQL Server 向臨時(shí)表插入數(shù)據(jù)示例

 更新時(shí)間:2014年06月12日 15:34:31   投稿:whsnow  
SQL Server 向臨時(shí)表插入數(shù)據(jù),用臨時(shí)表和表變量代替游標(biāo)會(huì)極大的提高性能,下面有個(gè)示例,大家可以參考下
復(fù)制代碼 代碼如下:

INSERT INTO #DirtyOldWIPBOM SELECT TOP (100) PERCENT dbo.WIP_BOM.Model, dbo.WIP_BOM.PartNumber,WIP_BOM.WIP
FROM dbo.WIP_BOM left OUTER JOIN dbo.BOM_CHINA ON LTRIM(dbo.WIP_BOM.Model) = LTRIM(dbo.BOM_CHINA.Model) AND LTRIM(dbo.WIP_BOM.PartNumber) = LTRIM(dbo.BOM_CHINA.PartNumber) AND dbo.WIP_BOM.Qty = dbo.BOM_CHINA.Qty AND BOM_CHINA.WIP=
WIP_BOM.WIP WHERE (dbo.BOM_CHINA.Model IS NULL) AND EXISTS(SELECT * FROM dbo.BOM_CHINA WHERE WIP = WIP_BOM.WIP AND LTRIM(Model) = LTRIM(WIP_BOM.Model))

這樣就可以成功。
復(fù)制代碼 代碼如下:

但SELECT TOP (100) PERCENT dbo.WIP_BOM.Model, dbo.WIP_BOM.PartNumber,WIP_BOM.WIP into #DirtyOldWIPBOM
FROM dbo.WIP_BOM left OUTER JOIN dbo.BOM_CHINA ON LTRIM(dbo.WIP_BOM.Model) = LTRIM(dbo.BOM_CHINA.Model) AND LTRIM(dbo.WIP_BOM.PartNumber) = LTRIM(dbo.BOM_CHINA.PartNumber) AND dbo.WIP_BOM.Qty = dbo.BOM_CHINA.Qty AND BOM_CHINA.WIP=
WIP_BOM.WIP WHERE (dbo.BOM_CHINA.Model IS NULL) AND EXISTS(SELECT * FROM dbo.BOM_CHINA WHERE WIP = WIP_BOM.WIP AND LTRIM(Model) = LTRIM(WIP_BOM.Model))

會(huì)提示error "There is already an object named '#DirtyOldWIPBOM' in the database"

為什么?

[筆記]:千萬不要用游標(biāo),用臨時(shí)表和表變量代替游標(biāo)會(huì)極大的提高性能,今天用游標(biāo)處理700行數(shù)據(jù)用了2小時(shí),用臨時(shí)表不到1秒就搞定。

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