Question

As the title states, I would like to know, before writing a join, if there is a way to write this query in rails.

I need to find every topic which has one post from user XXX.
What are the approach that is considered “correct” for this type of query in rails?

Edit 1:

My models are these actually:

• Topic has_many Comment
• Comment belongs_to User
• Comment belongs_to Topic
• User has_many Comment
• User has_many Topic

Answer 1

Try this:

Topic.joins(:comments).where('comments.user_id = ?', user.id).uniq