postgresql - Rails 应用程序中的 Heroku PostgreSQL GROUP_BY 错误

Question

我有一个在开发 (SQLite) 中运行良好的 Rails 应用程序，但是当我通过 Heroku 部署它时抛出了很多错误，我收集到它使用的是 PostgreSQL。

返回的错误信息:

        ActionView::Template::Error (PGError: ERROR:  
column "practices.id" must appear in the GROUP BY clause or be used in an aggregate function: 
SELECT "practices".* 
FROM "practices" WHERE ("practices".activity_id = 1) 
AND ("practices"."created_at" BETWEEN '2011-01-01' AND '2011-01-31') 
GROUP BY DATE(created_at) ORDER BY created_at DESC):

当我调用以下内容时会抛出此错误:

def month_days_not_practiced(date = Date.today)
   p = practices.where(:created_at => date.at_beginning_of_month..date.at_end_of_month).group("DATE(created_at)").to_a.count
   days_in_month(date.year, date.month) - p
end

我真的很想保持代码干净，以便它适用于开发和生产数据库......任何人都可以阐明一些问题吗？

我试过这个:

def month_days_not_practiced(date = Date.today)
   p = practices.where(:created_at => date.at_beginning_of_month..date.at_end_of_month).group("practices.id, DATE(created_at)").to_a.count
   days_in_month(date.year, date.month) - p
end

没用...

蒂亚。

Answer 1

Practice.group(Practice.col_list)



def self.col_list
  Practice.column_names.collect {|c| "practices.#{c}"}.join(",")
end