The last time we were together, we learned how to use the MERGE statement when we wanted to insert rows that didn’t exist and update rows that didn’t. This time we’re going to add onto that. We’re adding the seldom used, but delightfully potent – delete rows that no longer exist in the original table.
MERGE is an enticing but dangerous piece of syntax. It looks so nice until you realize how many bugs and oddities there are in the command.