SQL-按年，月，日分组的日期-更新 [英] SQL - date group by year, month, days - update

问题描述

我使用代码按年，月，日来计算两个日期组之间的差异：

I used code to calculate difference between two date group by year, months, date:

;WITH calendar AS (
SELECT  CAST(MIN([From date]) as datetime) as d,
    MAX([To date]) as e
FROM ItemTable
UNION ALL
SELECT  DATEADD(day,1,d),
    e
FROM calendar
WHERE d < e
), cte AS(
SELECT  i.Item,
    DATEPART(year,c.d) as [Year],
    DATEDIFF(month,MIN(c.d),MAX(c.d)) as NoOfMonth,
    DATEDIFF(day,DATEADD(month,DATEDIFF(month,MIN(c.d),MAX(c.d)),MIN(c.d)), 
  MAX(c.d)) as NoOfDays
FROM ItemTable i
INNER JOIN calendar c
ON c.d between i.[From date] and i.[To date]
GROUP BY i.Item, DATEPART(year,c.d),[From date],[To date]
)

SELECT  Item,
    [Year],
    SUM(NoOfMonth) as NoOfMonth,
    SUM(NoOfDays) as NoOfDays
FROM cte
GROUP BY Item,[Year]
ORDER BY Item
OPTION (MAXRECURSION 0)

我找到了此代码i n SQL-按年，月，日分组的日期

I found this code in SQL - date group by year, month, days

但不适用于我...

当我执行查询时

SELECT Item,
[From date],
[To date]
 from ItemDate;

我知道了

('A1','2013-08-27','2013-09-27'),
('A1','2013-09-28','2013-11-28'),
('A1','2013-11-30','2013-12-03'),
('A1','2013-12-31','2014-03-31'),
('A1','2014-04-01','2014-07-01'),
('A1','2014-07-02','2014-10-02'),
('A1','2014-10-03','2014-12-31')

，并从此链接执行代码 SQL-按年，月，日的日期分组

and when execute code from this link SQL - date group by year, month, days

我明白了：

 Item      Year         NoOfMonth     NoOfDays 
  A1        2013           4             -27
  A2        2014           10            58

这不好。...对于2013年，
应该是3个月零4天，对于2014年应该是11个月零28天

This is not good.... It should be 3 months and 4 day for year 2013, and for year 2014 11 month and 28 days

如何更新代码以获得所需的结果？

How to update the code to get the desired result?

推荐答案

C hange最后选择的内容：

Change the last select to:

SELECT  Item,
        [Year],
        CASE WHEN SUM(NoOfDays) < 0 THEN SUM(NoOfMonth)-1 
            WHEN SUM(NoOfDays) > 30 THEN SUM(NoOfMonth)+1 
            ELSE SUM(NoOfMonth) END as NoOfMonth,
        CASE WHEN SUM(NoOfDays) >= 30 THEN SUM(NoOfDays)-30 
            WHEN SUM(NoOfDays) < 0 THEN SUM(NoOfDays)+30
            ELSE SUM(NoOfDays) END as NoOfDays
FROM cte
GROUP BY Item,[Year]
ORDER BY Item
OPTION (MAXRECURSION 0)

此类报告的主要问题-很难定义什么是 1月，DATEDIFF只是从2个日期中取数字，然后从另一个日期中减去一个。

The main problem of such report - it is hard to define what is 1 month, DATEDIFF just takes number from 2 dates and subtract one from another.

我选择了30天作为月计数，现在我比较值30天中的某天，因此如果天数小于零或小于30

I have choose 30 as a days count in month, and now I compare values of days with 30 so we can add +1 to month if the day count goes under zero or below 30

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