Kevin Wilkie points out the numerous problems with the MERGE operator:
Now, when I last posted, I’m sure you thought I was done talking about the MERGE statement. You are so wrong, compadre! One more post is absolutely needed!
There are a few issues with the MERGE statement. Well, as of this writing, there are 361 possible issues according to Microsoft Connect – the actual website where Microsoft checks to see what issues exist!
So, if you want to use the MERGE statement, please read through every issue listed on the link above and make sure that none of those scenarios could exist for you. If they don’t, great. Knock yourself out and use it.
But wait, there’s more! Read on to see what else could be a problem.