Rails Scope for association of 0 size.
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MissingHandle
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Published on 2011-06-21T19:57:47Z
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2011/06/22
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ruby-on-rails
|activerecord
I'm having trouble figuring out the scope method for all the Foos that have no Bars. That is:
class Foo < ActiveRecord::Base
has_may :bars
end
class Bar < ActiveRecord::Base
belongs_to :foo
end
I'd like to write a scope method that returns me all the foos that have no bars. Something like:
class Foo < ActiveRecord::Base
has_may :bars
scope :has_no_bars, includes(:bars).where("COUNT(foo.bars) = 0")
end
But I don't understand the appropriate syntax. Any help? Happy to use a MetaWhere solution if easier.
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