See this blog post for what I am talking about: <a href="https:&#x2F;&#x2F;www.mssqltips.com&#x2F;sqlservertip&#x2F;3074&#x2F;use-caution-with-sql-servers-merge-statement&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.mssqltips.com&#x2F;sqlservertip&#x2F;3074&#x2F;use-caution-with...</a><p>If PostgreSQL had gone the same route as MS SQL I would have expected a similar set of bugs. I suspect all of this have been fixed by now, but I do not follow MS SQL.