ActiveRecord/Postgres：PGError必须出现在GROUP BY子句中或用于聚合函数

Question

在我的模型中，我有几个查询可以一个接一个地使用（和重用）。其中一个应该合计金额。这工作正常，在SQLite和抛出的Postgres上的错误：

ActiveRecord::StatementInvalid (PGError: ERROR: column "entries.date" must appear in the GROUP BY clause or be used in an aggregate function 
: SELECT sum(case when joint = false then amount else amount/2 end) as total, sum(case when joint = false then amount else 0 end) as sum_personal, sum(case when joint = true and user_id = 1 then amount/2 else 0 end) as sum_user_joint, sum(case when joint = true and user_id = 2 then amount/2 else 0 end) as sum_partner_joint FROM "entries" WHERE (1 = entries.user_id OR (2 = entries.user_id AND entries.joint = 't')) AND ('2011-04-01' <= entries.date AND entries.date <= '2011-04-30') AND (amount_calc > 0 AND compensation = 'f') ORDER BY date asc) 

Model.rb的有关部分

# all entries of one month 
    def self.all_entries_month(year, month, user_id, partner_id) 
    mydate = Date.new(year, month, 1) 

    where(':user_id = entries.user_id OR (:partner_id = entries.user_id AND entries.joint = :true)', { 
     :user_id => user_id, 
     :partner_id => partner_id, 
     :true => true 
    }). 
    where(':first_day <= entries.date AND entries.date <= :last_day', { 
     :first_day => mydate, 
     :last_day => mydate.at_end_of_month 
    }) 
    end 

    def self.income 
    where('amount_calc > 0 AND compensation = ?', false) 
    end 

    def self.cost 
    where('amount_calc <= 0 AND compensation = ?', false) 
    end 

    def self.order_by_date 
    order('date asc') 
    end 

    # group by tag and build sum of groups named group_sum 
    def self.group_by_tag(order) 
    group('tag'). 
    select('tag, ' + 
      'sum(case when joint = "f" then amount else amount/2 end) as tag_sum' 
     ). 
    order('tag_sum ' + order) 
    end 

    def self.multiple_sums(user_id, partner_id) 
    case ActiveRecord::Base.connection.adapter_name 
     when 'SQLite' 
     select('sum(case when joint = "f" then amount else amount/2 end) as total, ' + 
       'sum(case when joint = "f" then amount else 0 end) as sum_personal, ' + 
       'sum(case when joint = "t" and user_id = ' + user_id.to_s + ' then amount/2 else 0 end) as sum_user_joint, ' + 
       'sum(case when joint = "t" and user_id = ' + partner_id.to_s + ' then amount/2 else 0 end) as sum_partner_joint ' 
     ) 
     when 'PostgreSQL' 
     select('sum(case when joint = false then amount else amount/2 end) as total, ' + 
       'sum(case when joint = false then amount else 0 end) as sum_personal, ' + 
       'sum(case when joint = true and user_id = ' + user_id.to_s + ' then amount/2 else 0 end) as sum_user_joint, ' + 
       'sum(case when joint = true and user_id = ' + partner_id.to_s + ' then amount/2 else 0 end) as sum_partner_joint ' 
     ) 
    else 
     raise 'Query not implemented for this DB adapter' 
    end 
    end 

控制器

# get all entries of given month 
@cost = Entry.all_entries_month(@year, @month, current_user.id, current_partner.id).cost 

# group cost by categories 
@group_cost = @cost.group_by_tag('asc') 

# still need to sort by date 
@cost = @cost.order_by_date 

@calc_cost = @cost.multiple_sums(current_user.id, current_partner.id)[0] 

我怎样才能改变我的查询multiple_sums没有打破其他查询？或者，我是否需要在不使用现有的多个地面的情况下实施多个地震？

Answer 1

删除order by子句，因为无论如何，因为您正在分组为单个行，所以无用。

请 - 重新格式化您的查询，以便他们将可见和可读。