There is no good old idea, but that somebody else didn't think of it first. I bet somewhere out there is a statistician from the 1940s with a box of those cards with holes and notches you used as a DB "join" method over fields saying "...have I got a story for you..." (I used them in school btw. I had a real moment in DB class learning JOIN and thinking back to how we did selection over multiple criteria from these cards)