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我有一個名爲Answer
的模型與has_one Question
關聯。 Question
有dimension_id, possible_answers
我有以下查詢通過自定義字段的Ruby ActiveRecord查詢總和
Answer.joins(:question).select(:dimension_id,"(CAST(answers.answer AS FLOAT)/(length(possible_answers))) AS satisfaction").where(:created_at => date_from..date_to)
我想組由dimension_id和總和滿意的結果,爲了得到每個維度的滿意度,但如果我不.group(:dimension_id).sum(:satisfaction)
我得到的錯誤PG::UndefinedColumn: ERROR: column "satisfaction" does not exist
我應該如何總結滿意度以獲得理想的結果? 謝謝
(dimension_id是個問題)。如果我這樣做,我得到:PG :: GroupingError:錯誤:列「answers.answer」必須出現在GROUP BY子句中或用於聚合函數中 LINE 1:SELECT questions.dimension_id,(CAST(answers.answer AS FLOAT – marimaf