根据另一个表的值更新字段 [英] Update Field based on another table's values

问题描述

是否有更优雅的方式来编写以下 Microsoft SQL Server 2008 命令?

Is there a more elegant way to write the following Microsoft SQL Server 2008 command?

UPDATE TableB
SET TableBField2=0
WHERE TableBID IN(
     SELECT TableBID 
     FROM TableB
     JOIN TableA on TableB.TableAID=TableA.TableAID
     WHERE TableBField2 < 0
     AND TableAField1 = 0
)

简单地说，我正在做的是根据连接表中字段的值更新表.我想知道我对 IN() 的使用是否被认为是低效的.

In plain speak, what I'm doing is updating a table based on the value of a field in a joined table. I wonder if my use of IN() is considered inefficient.

推荐答案

这样应该更有效率:

UPDATE TableB b
SET TableBField2=0
WHERE exists (
     SELECT 1
     FROM TableA
     WHERE b.TableAID=TableA.TableAID
     AND b.TableBField2 < 0
     AND TableAField1 = 0
)

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