Select distinct … inner join vs. select … where id in (…)

Question

I\'m trying to create a subset of a table (as a materialized view), defined as those records which have a matching record in another materialized view.

For example,

Answer 1

This will depend on the data you have, but using Distinct within the join could improve your performance:

Select u.*
From Users u
Join ( Select Distinct user_id
       From log_mview ) l On u.user_id = l.user_id