What was your coolest SQL optimization, on a slow performing query?

Question

Just speaking to a colleague of mine. He was walking with a hop in his step, on the way to the coffee machine.

I asked him \"what\'s with the \'swarmy\' walk?\", he said

Answer 1

Changing order of conditions inside WHERE clause so it filters the most discriminating condition first (while at the same time indexes from non-discriminating columns like gender are removed).