我有一个名为Answer的模型，其中包含has_one Question。
Question有dimension_id, possible_answers
我有以下查询
Answer.joins(:question).select(:dimension_id,"(CAST(answers.answer AS FLOAT) / (length(possible_answers))) AS satisfaction").where(:created_at => date_from..date_to)
我想按维度_id对结果进行分组，并按满意度求和，以便获得每个维度的满意度，但如果我.group(:dimension_id).sum(:satisfaction)我收到错误PG::UndefinedColumn: ERROR: column "satisfaction" does not exist
我应该如何总结满意度以获得理想的结果？ 谢谢
答案 0 :(得分：0)
尝试这种方式：
Answer.where(:created_at => date_from..date_to).joins(:question).select("answers.dimension_id, sum(CAST(answers.answer AS FLOAT) / (length(possible_answers))) AS satisfaction").group('answers.dimension_id')
我认为您的dimension_id位于answers，如果没有将answers.dimension_id更改为questions.dimension_id