我正在跟随Bate的图形和图表教程,但是出现了一个错误。
这是我得到的错误消息:
PG::Error: ERROR: column "orders.created_at" must appear in the GROUP BY clause or be used in an aggregate function
LINE 1: SELECT created_at, sum(amount) as total_amount FROM "orders"...
^
: SELECT created_at, sum(amount) as total_amount FROM "orders" WHERE ("orders"."created_at" BETW
这是我在我的订单模型中使用的代码
def self.total_grouped_by_day(start)
orders = where(created_at: start.beginning_of_day..Time.zone.now)#.all
orders = orders.group("date(created_at)")
orders = orders.select("date(created_at), sum(amount) as total_amount")
orders.group_by { |order| order.created_at.to_date }
end
在我的帮助器中
def orders_chart_data
orders_by_day = Order.total_grouped_by_day(3.weeks.ago)
(3.weeks.ago.to_date..Date.today).map do |date|
{
created_at: date,
price: orders_by_day[date].first.try(:total_amount) || 0
}
end
end
我正在使用Postgres(我相信这是导致此错误的主要原因)和Rails 3.x.x。
为什么会出现这个错误,我该如何解决?
提前感谢您的帮助。
在我的控制台中:
Order.where(created_at: 3.weeks.ago.beginning_of_day..Time.zone.now).group("date(created_at)").select("date(created_at), sum(amount) as total_amount")
& 这就是我得到的内容
[#<Order >, #<Order >, #<Order >]
很奇怪...
在我的控制台中运行以下代码:Order.where(created_at: 3周前的开始时间..Time.zone.now).group("date(created_at)").select("date(created_at), sum(amount) as total_amount").first.total_amount
会得到这个结果:
Creating scope :page. Overwriting existing method Order.page.
Order Load (18.1ms) SELECT date(created_at), sum(amount) as total_amount FROM "orders" WHERE ("orders"."created_at" BETWEEN '2013-07-05 00:00:00.000000' AND '2013-07-26 23:50:38.876609') GROUP BY date(created_at) LIMIT 1
=> "10.0"