SQL Server是否支持IS DISTINCT FROM子句？

Question

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

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; 

Answer 1

不，它不会被改写。下面的SO问题解释了如何将其改写成等价（但更详细）的SQL Server表达式：

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

还有针对此问题，在这里你可以投票包含在Microsoft连接入口下一个版本：

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