Chad Callihan shows off a good use of aggregate functions and the CASE statement:
Have you have been tasked with pulling multiple counts from the same table? Maybe you need to find how many records have a value for a column and how many are NULL. Or maybe you need to see how many records are true and how many are false.
It’s simple enough to run a query to count one set of criteria, run another query for the second set of criteria, and combine them when sending your results. Did you know you can get multiple counts with one query?
Here’s an example of how using COUNT and CASE can speed up your day.
Click through for an example. I mildly disagree with Chad’s conclusion that this is something you’ll rarely do—the more you work with reporting and analytical queries, the more you’ll appreciate this.