Subject Re: IN, sub-select and select distinct
Author Svein Erling
> I can't believe there is no way to achieve the "explicit IN"
> performance with a JOIN, a sub-select or anything else.

I generally like using EXISTS, but I don't think it can beat the
alternatives already mentioned. And trying to look up values anywhere
can never beat hardcoding values, it is like trying to access the
harddisk quicker than the RAM.

If this is a query that is executed often and speed is essential, then
I'd say your only really quick alternative would be to make another
table and populate it through AFTER INSERT/UPDATE/DELETE triggers from
your main table. Then you could simply do
SELECT <whatever> FROM <NewTriggerPopulatedTable>
whenever you needed these values.