SQL Server 是否支持 IS DISTINCT FROM 子句?

2022-01-16 00:00:00 sql distinct sql-server-2008 sql-server sql-server-2008-r2

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，它没有.以下 SO 问题解释了如何将它们重写为等效(但更详细)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IS DISTINCT FROM和IS NOT DISTINCT FROM?

还有一个针对此问题的 Uservoice 条目，您可以在其中投票支持将其纳入下一版本:

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

  • 添加对 ISO <distinct predicate>
    • 的语言和优化器支持
  • Add language and optimizer support for ISO <distinct predicate>

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