Question

您好，我有这样的计划表;

<ActiveRecord::Relation [#<Schedule id: 427, date: "2016-06-15", notes: nil, price: "350", promo: "", status: "available", boat_id: 45, created_at: "2016-06-09 19:43:15", updated_at: "2016-06-09 19:43:15">, #<Schedule id: 428, date: "2016-06-16", notes: nil, price: "350", promo: "", status: "available", boat_id: 45, created_at: "2016-06-09 19:43:15", updated_at: "2016-06-09 19:43:15">, #<Schedule id: 429, date: "2016-06-17", notes: nil, price: "350", promo: "", status: "available", boat_id: 45, created_at: "2016-06-09 19:43:15", updated_at: "2016-06-09 19:43:15">, #<Schedule id: 430, date: "2016-06-22", notes: "", price: "253", promo: "", status: "available", boat_id: 3, created_at: "2016-06-14 09:23:55", updated_at: "2016-06-14 09:23:55">, #<Schedule id: 431, date: "2016-06-23", notes: "", price: "253", promo: "", status: "available", boat_id: 3, created_at: "2016-06-14 09:23:55", updated_at: "2016-06-14 09:23:55">]

和用户输入“from”和“to”日期。假设我有变量

a = "2016-06-16".in_time_zone('UTC')
b = "2016-06-19".in_time_zone('UTC')

我想在这些日期（a和b）之间循环调度表并获得价格总和..

我想到了一个这样的解决方案，我可以说;

a = "2016-06-16".in_time_zone('UTC')
b = "2016-06-19".in_time_zone('UTC')
schedules = Schedule.all
price = 0

dates = []
while a < b do
 dates << a
 a += 1.day
end

然后;

dates.each do |date|
  schedules.each do |schedule|
    if (date == schedule.in_time_zone('UTC'))
      price += schedule.price.to_i
    end
  end
end

但不知道这是否是最便捷的方式。

Answer 1

为什么不利用数据库原生实现。您可以在SQL中执行此操作。

date_from = "2016-06-16".in_time_zone('UTC')
date_to   = "2016-06-19".in_time_zone('UTC')

Schedule
  .where(date: date_from..date_to) # sql BETWEEN operator
  .sum("price") # SQL aggregate function.

Ruby循环日期

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