Does SQL Server support IS DISTINCT FROM clause?

问题

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;

can be rewritten using IS DISTINCT FROM

SELECT * FROM Bugs WHERE assigned_to IS DISTINCT FROM 1;

回答1:

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

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

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

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

来源：https://stackoverflow.com/questions/12456737/does-sql-server-support-is-distinct-from-clause