Scope with aggregate functions on associations

Space has_many spacephotos

scope :with_photos, -> { joins(:spacephotos).group("spaces.id").having("count(*) > 0") }

Space.with_photos
=> SELECT "spaces".* FROM "spaces" INNER JOIN "spacephotos" ON "spacephotos"."space_id" = "spaces"."id" GROUP BY spaces.id HAVING count(*) > 0

Space.with_photos.count
=> SELECT COUNT(*) AS count_all, spaces.id AS spaces_id FROM "spaces" INNER JOIN "spacephotos" ON "spacephotos"."space_id" = "spaces"."id" GROUP BY spaces.id HAVING count(*) > 0