4 ms·

I wonder if NOT NOT IN would have solved it since he mentions the problem doesn't exist for NOT IN.

• jswinghammer 15y ago
  No. MySQL is able to optimize an anti-join but not the IN condition. It works about the same as having a LEFT JOIN with a not is null check in the where clause. MySQL will see NOT NOT IN as just IN.
  • Hawramani 15y ago
    Would using parentheses (NOT(NOT IN...)) make a difference?
    • jswinghammer 15y ago
      Using NOT NOT IN is a syntax error in any event. I was answering in the hypothetical in any event.
      • Hawramani 15y ago
        Ah I see. Thanks for the answer.