This article was written by a co-worker of mine and I wanted to share with everyone else.

Temporary Tables. What are they? Why are they bad? You might think you don’t explicitly use any, but in actuality you may be using them all the time.

Temporary tables come in two flavors. The kind you know you’re making, and the kind you don’t. You know you’re making a temporary table when you use the CREATE TEMPORARY TABLE syntax. On the other hand, there are lots of other cases in which MySQL will create a temporary table for you, in the background, to help out the query execution to get you your results.
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