SQL Server是否支持IS DISTINCT FROM子句？ [英] Does SQL Server support IS DISTINCT FROM clause?

问题描述

SQL Server是否支持SQL：1999标准的 IS DISTINCT FROM 语句？例如。查询

Does SQL Server support IS DISTINCT FROM statement which is SQL:1999 standard? E.g. the query

SELECT * FROM Bugs WHERE assigned_to IS NULL OR assigned_to <> 1;

可以使用 IS DISTINCT FROM

SELECT * FROM Bugs WHERE assigned_to IS DISTINCT FROM 1;

推荐答案

不，不是。以下SO问题说明了如何将它们重写为等效（但更冗长）的SQL Server表达式：

No, it doesn't. The following SO question explains how to rewrite them into equivalent (but more verbose) SQL Server expressions:

• 如何重写是不同的还是不是不同的？

• How to rewrite IS DISTINCT FROM and IS NOT DISTINCT FROM?

还有一个针对此问题的Uservoice条目，您可以在其中投票以将其包含在下一个发行版中：

There's also a Uservoice entry for this issue, where you can vote for inclusion in the next release:

• 为ISO添加语言和优化程序支持< distinct谓词>

• Add language and optimizer support for ISO <distinct predicate>

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