MySQL “IN” operator performance on (large?) number of values

Question

I have been experimenting with Redis and MongoDB lately and it would seem that there are often cases where you would store an array of id\'s in either Mongo

Answer 1

IN is fine, and well optimized. Make sure you use it on an indexed field and you're fine.

It's functionally equivalent to:

(x = 1 OR x = 2 OR x = 3 ... OR x = 99)

As far as the DB engine is concerned.