Method: ActiveRecord::SpawnMethods#merge

Defined in:
lib/active_record/relation/spawn_methods.rb

#merge(other) ⇒ Object

Merges in the conditions from other, if other is an ActiveRecord::Relation. Returns an array representing the intersection of the resulting records with other, if other is an array.

Post.where(published: true).joins(:comments).merge( Comment.where(spam: false) )
# Performs a single join query with both where conditions.

recent_posts = Post.order('created_at DESC').first(5)
Post.where(published: true).merge(recent_posts)
# Returns the intersection of all published posts with the 5 most recently created posts.
# (This is just an example. You'd probably want to do this with a single query!)

Procs will be evaluated by merge:

Post.where(published: true).merge(-> { joins(:comments) })
# => Post.where(published: true).joins(:comments)

This is mainly intended for sharing common conditions between multiple associations.



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# File 'lib/active_record/relation/spawn_methods.rb', line 29

def merge(other)
  if other.is_a?(Array)
    to_a & other
  elsif other
    spawn.merge!(other)
  else
    self
  end
end