MSSQL 记一次删除数据特别慢

Posted 2020-11-17 love-zf

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["Table闪亮登场"]

主表:Base(BaseID Int,BaseName Nvarchar(200))

关系表:BaseForUser(BaseForUserID Int,BaseID Int)

["一些描述“]

要删除BaseID为1数据,当然BaseForUser中BaseID为1的数据也要删除...
(并且要删除的数据还不多,Base表一条数据,BaseForUser表中10条数据左右)
But  BaseForUser中数据比较多(客户比较多，你懂得),一亿多...

["第一个版本"]

Declare @BaseID Int = 1
Delete From BaseForUser Where BaseID = @BaseID

Delete From Base Where BaseID = @BaseID

--耗时 1分钟多...Pass

 

["第2个版本"]

第二个版本:
Delete Base From (Select BaseID From BaseForUser Where BaseID = @BaseID) U Where Base.BaseID = U.BaseID

--耗时50s...Pass

 

["第③个版本"]

--确定范围
Declare @User Table(BaseForUserID Int Primary Key)
Insert Into @User 
Select T.ClassTableGenerateForStudentID 
From BaseForUser U With(NoLock)
Where U.BaseID = @BaseID

Delete From BaseForUser
Where BaseForUserID Between ( Select Min(BaseForUserID) From @User ) 
And ( Select Max(BaseForUserID) From @User ) And BaseID = @BaseID

--耗时10s，好吧，先这样吧...-_-||

 

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