CODEWITHSUNDEEP
ruby-on-railsactiverecordhas-many-through
Jesse Farmer
Jesse Farmer

Reputation: 459

Rails, ActiveRecord, has_many :through: find all records for which there is no Association

I have a typical has_many :through relationship between Menu and Section called Sectionalization. Sections go on Menus. Some Sections are on no Menu.

I need a collection of all the Section records for which there is no Sectionalization record with a matching section_id (Sections that are on NO other Menu).

Upvotes: 0

Views: 175

Answers (1)

Peter Alfvin
Peter Alfvin

Reputation: 29389

As far as I know this requires an outer join which in turn requires that you specify it with your own SQL fragment, as follows:

Section.joins('LEFT OUTER JOIN sectionalizations on sections.id = sectionalizations.section_id).where('sectionalizations.section_id IS NULL)

Upvotes: 1

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