Very helpful SQL Server 2005+ commands:
I had to find the different rows of two pretty complex, non-related queries, and decided to look up if there was an easier way to do than by exploiting UNION (a technique I think I picked up from the same author, actually...). Turns out you just need to put and EXCEPT in between the queries. That's it.
I just found this last week and have probably already used it five times. It makes me want to get a book on SQL Server 2008 to see what other time-savers I can find, especially I'm analyzing LOTS of data these days.