I have a simple association like:
class User < ActiveRecord::Base
has_many :photos
end
class Photo < ActiveRecord::Base
belongs_to :user
# Photo fields => id, image, photo_type
end
In the photo model photo_type value can be in 'personal', family' or 'official'.
What is the best way to get all users either have NO photos OR photo_type != 'personal'(if the user has photos)?
I'd appreciate any help. Thanks!
I've flagged a duplicate which has lots of answers, but in a nutshell, you could use:
# No photos
User.includes(:photos).where( photos: { user_id: nil } )
# Not personal
User.includes(:photos).where.not( photos: { photo_type: "personal" } )
# Users with photos, where the `photo_type` isn't "personal"
User.includes(:photos).where.not( photos: { user_id: nil, photo_type: "personal" } )
There's also a Rails 5 approach that avoids loading the association, though I've not used yet personally:
User.left_outer_joins(:photos).where.not( photos: { user_id: nil, photo_type: "personal" } )
How does that look? The last option do what you're after?
Let me know if you've any questions.
