What's the difference between “includes” and “joins” in ActiveRecord query?

Question

What\'s the difference between \"includes\" and \"joins\" in ActiveRecord query? Can anyone explain to me with the following two associated

Answer 1

:joins joins tables together in sql, :includes eager loads associations to avoid the n+1 problem (where one query is executed to retrieve the record and then one per association which is loaded).

I suggest you read their sections in Rails Guides to get more info.