我有以下脚本：
User.includes(:owned_ratings).map{|x| x.owned_ratings.average(:score)}
调用x.owned_ratings.average(：score)会导致n 1个查询：
(0.2ms) SELECT AVG("ratings"."score") FROM "ratings" INNER JOIN "video_chats" ON "ratings"."video_chat_id" = "video_chats"."id" WHERE "video_chats"."user_id" = $1 [["user_id",4]]
(0.1ms) SELECT AVG("ratings"."score") FROM "ratings" INNER JOIN "video_chats" ON "ratings"."video_chat_id" = "video_chats"."id" WHERE "video_chats"."user_id" = $1 [["user_id",1]]
(0.1ms) SELECT AVG("ratings"."score") FROM "ratings" INNER JOIN "video_chats" ON "ratings"."video_chat_id" = "video_chats"."id" WHERE "video_chats"."user_id" = $1 [["user_id",5]]
(0.1ms) SELECT AVG("ratings"."score") FROM "ratings" INNER JOIN "video_chats" ON "ratings"."video_chat_id" = "video_chats"."id" WHERE "video_chats"."user_id" = $1 [["user_id",7]]
(0.1ms) SELECT AVG("ratings"."score") FROM "ratings" INNER JOIN "video_chats" ON "ratings"."video_chat_id" = "video_chats"."id" WHERE "video_chats"."user_id" = $1 [["user_id",3]]
为什么包含不使用聚合方法？有什么方法可以解决这个问题吗？我知道我可以自己实现平均方法并省略问题,但我想确保没有更好的解决方案.