Question

I have a query:

UPDATE table_1 set field_1 = 1 where field_2 IN 
(SELECT field_2 from table_2 where field_3 = 1)

However this takes a LONG time with a large database (>2000ms). Is there anway to re-write this query using JOINs to get away from using IN?

NOTE: There are indexes on field_1, and field_3 however it doesn’t help the query. This is using MySQL.

Answer 1

UPDATE table_1, table_2
    SET table_1.field_1 = 1
    WHERE table_1.field_2 = table_2.field_2
        AND table_2.field_3 = 1