Моя пользовательская модель имеет следующее определение для ассоциации follower:
has_many :passive_follow_actions, -> { where("actions.activity_verb = 'follow'").uniq }, class_name: 'Action', foreign_key: :activity_object_id
has_many :followers, through: :passive_follow_actions, source: :activity_actor, source_type: 'User'
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В таблице пользователей есть поле jsonb с именем follow_stats, которое я использую для упорядочения результатов подписчика.
Вкл.отдельная отдельная операция работает
has_many :followers, -> { distinct }, through: :passive_follow_actions, source: :activity_actor, source_type: 'User'
# SELECT DISTINCT "users".* FROM "users" INNER JOIN "actions" ON "users"."id" = "actions"."activity_actor_id" WHERE "actions"."activity_object_id" = 1 AND (actions.activity_verb = 'follow') AND "actions"."activity_actor_type" = 'User'
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Также сама операция заказа работает
has_many :followers, -> { order("follow_stats->'followers_count' DESC") }, through: :passive_follow_actions, source: :activity_actor, source_type: 'User'
# SELECT "users".* FROM "users" INNER JOIN "actions" ON "users"."id" = "actions"."activity_actor_id" WHERE "actions"."activity_object_id" = 1 AND (actions.activity_verb = 'follow') AND "actions"."activity_actor_type" = 'User' ORDER BY follow_stats->'followers_count' DESC
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Однако, вместе взятая,
has_many :followers, -> { distinct.order("follow_stats->'followers_count' DESC") }, through: :passive_follow_actions, source: :activity_actor, source_type: 'User'
# SELECT DISTINCT "users".* FROM "users" INNER JOIN "actions" ON "users"."id" = "actions"."activity_actor_id" WHERE "actions"."activity_object_id" = 1 AND (actions.activity_verb = 'follow') AND "actions"."activity_actor_type" = 'User' ORDER BY follow_stats->'followers_count' DESC
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она выбрасываетследующее исключение:
PG::InvalidColumnReference: ERROR: for SELECT DISTINCT, ORDER BY expressions must appear in select list
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Я попытался добавить запрос jsonb в предложение select, чтобы предотвратить ошибку, но это приводит к пустому ответу:
has_many :followers, -> { select("follow_stats->'followers_count'").uniq.order("follow_stats->'followers_count' DESC") }, through: :passive_follow_actions, source: :activity_actor, source_type: 'User'
# SELECT DISTINCT follow_stats->'followers_count' FROM "users" INNER JOIN "actions" ON "users"."id" = "actions"."activity_actor_id" WHERE "actions"."activity_object_id" = 1 AND (actions.activity_verb = 'follow') AND "actions"."activity_actor_type" = 'User' ORDER BY follow_stats->'followers_count' DESC
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Ответ:
[#<User id: nil, ?column?: 42>, #<User id: nil, ?column?: 4>, #<User id: nil, ?column?: 2>, #<User id: nil, ?column?: 1>, #<User id: nil, ?column?: 0>]
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Когда я добавляю * в предложении select, он возвращает то же исключение PG :: InvalidColumnReference
has_many :followers, -> { select("*, follow_stats->'followers_count'").uniq.order("follow_stats->'followers_count' DESC") }, through: :passive_follow_actions, source: :activity_actor, source_type: 'User'
#SELECT DISTINCT *, follow_stats->'followers_count' FROM \"users\" INNER JOIN \"actions\" ON \"users\".\"id\" = \"actions\".\"activity_actor_id\" WHERE \"actions\".\"activity_object_id\" = 1 AND (actions.activity_verb = 'follow') AND \"actions\".\"activity_actor_type\" = 'User' ORDER BY follow_stats->'followers_count' DESC
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Как выбрать отличительные и упорядоченные по ключу jsonb одновременно?