Display Users without Posts in Rails -

how query users have yet write posts? trying:

u = user.joins(:posts).where('posts.size = ?', 0)

output:

pg::undefinedcolumn: error:  column posts.size not exist

trying wrap head around correct sql syntax, no luck far

you must without join, this:

 user.where(post.where("posts.user_id = users.id").exists.not)

its useful chain conditions (like applying different filters).

creates sql like:

select "users".* "users"   (   not (     exists (select "posts".* "posts"  (posts.user_id = users.id))   ) )

Braziel