I came across this interesting and helpful blog post by one Hugo Kornelis :-).
Hence a double thank you to Hugo for an excellent QotD on MERGE following the ANSI standard, and for sharing your extensive knowledge with everybody on the web.l
Thank you Michael (and Hugo!) for that very useful link.
Despite my minor bit of pedantry about the SQL versions, I second your thanks to Hugo - I always read his contributions with interest and often learn from them. 🙂