JoshTGreenwood/ar_merge.md

## ar_merge.md

      
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              ar_merge.md
            
          
    TIL #merge is a thing on AR models.
Useful for joining + using a named scoped on the joined table:
class Post; end
class Comment; scope :approved, -> {approved: true}; end
Post.joins(:comments).merge(Comment.approved)

vs.
Post.joins(:comments).where(comments: {approved: true})  # this requires duplicating the logic defined in your scope