Question

假设，2017年5月，我想获得2017年4月的记录。

我的查询会记录2017年4月的记录，但我也希望包含空日期。

因此，所需的输出将如下：

----------------------
id | date     | count
----------------------
1  | 01/04/17 |  0    // 0 because this dates does not have any tickets.
2  | 02/04/17 |  0    // 0 because this dates does not have any tickets.
3  | 03/04/17 |  0    // 0 because this dates does not have any tickets.
4  | 04/04/17 |  0    // 0 because this dates does not have any tickets.
5  | 05/04/17 |  0    // 0 because this dates does not have any tickets.
6  | 06/04/17 |  0    // 0 because this dates does not have any tickets.
7  | 07/04/17 |  0    // 0 because this dates does not have any tickets.
8  | 08/04/17 |  0    // 0 because this dates does not have any tickets.

直到30/04/2017

15/04/17显示2个计数，因为它包含2个记录，我的查询也说明了这一点但如何从01/04/17 - 30/04/2017

开始包含空日期

查询是：

Ticket.includes(:line_items).where('tickets.created_at > ? AND 
tickets.created_at < ?', Date.today.last_month.beginning_of_month, 
Date.today.beginning_of_month).where.not(line_items: {id: nil}).count

输出是：

SELECT COUNT(DISTINCT "tickets"."id") FROM "tickets" LEFT OUTER JOIN 
"line_items" ON "line_items"."ticket_id" = "tickets"."id" WHERE 
(tickets.created_at > '2017-04-01' AND tickets.created_at < '2017-05-01') AND 
("line_items"."id" IS NOT NULL)

所需的输出应显示如下记录：

同样，如果用户选择过去7天，它也应显示最近7天的记录。

应对它的任何解决方法？

Answer 1

假设您将用户输入存储在名为“no_of_days”的变量中。你可以做点什么

data = Ticket.includes(:line_items).where('tickets.created_at > ? AND tickets.created_at < ?', Time.now.beginning_of_day - (no_of_days).days , Time.now.beginning_of_day).where.not(line_items: {id: nil}) #retrieves all data in a single query

(0..no_of_days).map do |day_from_now|
  todays_data = data.select{|item| item.created_at < (Time.now.beginning_of_day - (day_from_now).days) && item.created_at > (Time.now.beginning_of_day - (day_from_now - 1).days)}
 return { "day": (Date.today - day_from_now.days).strftime("%A %d-%m"), 
  "ticket_count": todays_data.size, 
  "total_sales": todays_data.inject(0){|sum, item| sum + item.line_item.quantity * item.line_item.rate }
end

Answer 2

在 SQL-Server 中，您可以实现以下目标：

DECLARE @MinDate DATE = '20170401',
        @MaxDate DATE = '20170430';
SELECT t.Id, d.[Date], COALESCE(t.[Count],0) AS [Count]
FROM (
SELECT  TOP (DATEDIFF(DAY, @MinDate, @MaxDate) + 1)
        Date = DATEADD(DAY, ROW_NUMBER() OVER(ORDER BY a.object_id) - 1, @MinDate)
FROM    sys.all_objects a
        CROSS JOIN sys.all_objects b
) d
LEFT JOIN yourTbl AS t ON d.Date = t.Date

Answer 3

回答PostgreSQL，但不是RoR，因为我不知道：

SELECT dat::date, count(DISTINCT tic."id")
  FROM generate_series('2017-04-01'::date, '2017-04-30'::date, interval '1 day') AS dat
  LEFT JOIN (SELECT "tickets"."id", "tickets"."created_at"
               FROM "tickets"
               JOIN "line_items"
                 ON "line_items"."ticket_id" = "tickets"."id") tic
  ON tic."created_at" = dat::date
 GROUP BY dat
 ORDER BY dat

或

SELECT dat::date, count(DISTINCT "tickets"."id")
  FROM generate_series('2017-04-01'::date, '2017-04-30'::date, interval '1 day') AS dat
  LEFT JOIN "tickets" ON "tickets"."created_at" = dat::date
                     AND EXISTS(SELECT 1 FROM "line_items"
                                 WHERE "line_items"."ticket_id" = "tickets"."id" LIMIT 1)
 GROUP BY dat
 ORDER BY dat

generate_series创建的行集从param1到param2，间隔为param3。

Group By记录基于开始日期和结束日期的计数Rails

3 个答案: