Question

我是SQL的新手，如果我使用错误的术语并且我编写的代码是可怕的，那么道歉。

我正在尝试创建一个查询来输出每年每月的天数。我创建的测试表是datetest：

startdate    enddate
2105-12-16   2016-02-15
2017-01-01   2017-01-02

并使用下面粘贴的查询得到以下结果：

Year  Jan  Feb  Mar  Apr  May  Jun  Jul  Aug  Sep  Oct  Nov  Dec
2015  31   15   0    0    0    0    0    0    0    0    0    16
2017  4    0    0    0    0    0    0    0    0    0    0    0

我遇到的问题是，当日期范围超过两年时，结果会落在开始日期年份而非实际年份。

如果有人可以提供帮助，我会非常感激感谢

查询

SELECT
year(startdate) AS Year,

SUM(GREATEST(datediff(least(CAST(CONCAT(YEAR(startdate), '-01-31') AS DATETIME),enddate),greatest(CAST(CONCAT(YEAR(startdate), '-01-01') AS DATETIME),startdate))+1,0))+SUM(GREATEST(datediff(least(CAST(CONCAT(YEAR(enddate), '-01-31') AS DATETIME),enddate),greatest(CAST(CONCAT(YEAR(enddate), '-01-01') AS DATETIME),startdate))+1,0)) AS "Jan",

SUM(GREATEST(datediff(least(CAST(CONCAT(YEAR(startdate), '-02-28') AS DATETIME),enddate),greatest(CAST(CONCAT(YEAR(startdate), '-02-01') AS DATETIME),startdate))+1,0))+SUM(GREATEST(datediff(least(CAST(CONCAT(YEAR(enddate), '-02-28') AS DATETIME),enddate),greatest(CAST(CONCAT(YEAR(enddate), '-02-01') AS DATETIME),startdate))+1,0)) AS "Feb",

SUM(GREATEST(datediff(least(CAST(CONCAT(YEAR(startdate), '-03-31') AS DATETIME),enddate),greatest(CAST(CONCAT(YEAR(startdate), '-03-01') AS DATETIME),startdate))+1,0))+SUM(GREATEST(datediff(least(CAST(CONCAT(YEAR(enddate), '-03-31') AS DATETIME),enddate),greatest(CAST(CONCAT(YEAR(enddate), '-03-01') AS DATETIME),startdate))+1,0)) AS "Mar",

SUM(GREATEST(datediff(least(CAST(CONCAT(YEAR(startdate), '-04-30') AS DATETIME),enddate),greatest(CAST(CONCAT(YEAR(startdate), '-04-01') AS DATETIME),startdate))+1,0))+SUM(GREATEST(datediff(least(CAST(CONCAT(YEAR(enddate), '-04-30') AS DATETIME),enddate),greatest(CAST(CONCAT(YEAR(enddate), '-04-01') AS DATETIME),startdate))+1,0)) AS "Apr",

SUM(GREATEST(datediff(least(CAST(CONCAT(YEAR(startdate), '-05-31') AS DATETIME),enddate),greatest(CAST(CONCAT(YEAR(startdate), '-05-01') AS DATETIME),startdate))+1,0))+SUM(GREATEST(datediff(least(CAST(CONCAT(YEAR(enddate), '-05-31') AS DATETIME),enddate),greatest(CAST(CONCAT(YEAR(enddate), '-05-01') AS DATETIME),startdate))+1,0)) AS "May",

SUM(GREATEST(datediff(least(CAST(CONCAT(YEAR(startdate), '-06-30') AS DATETIME),enddate),greatest(CAST(CONCAT(YEAR(startdate), '-06-01') AS DATETIME),startdate))+1,0))+SUM(GREATEST(datediff(least(CAST(CONCAT(YEAR(enddate), '-06-30') AS DATETIME),enddate),greatest(CAST(CONCAT(YEAR(enddate), '-06-01') AS DATETIME),startdate))+1,0)) AS "Jun",

SUM(GREATEST(datediff(least(CAST(CONCAT(YEAR(startdate), '-07-31') AS DATETIME),enddate),greatest(CAST(CONCAT(YEAR(startdate), '-07-01') AS DATETIME),startdate))+1,0))+SUM(GREATEST(datediff(least(CAST(CONCAT(YEAR(enddate), '-07-31') AS DATETIME),enddate),greatest(CAST(CONCAT(YEAR(enddate), '-07-01') AS DATETIME),startdate))+1,0)) AS "Jul",

SUM(GREATEST(datediff(least(CAST(CONCAT(YEAR(startdate), '-08-31') AS DATETIME),enddate),greatest(CAST(CONCAT(YEAR(startdate), '-08-01') AS DATETIME),startdate))+1,0))+SUM(GREATEST(datediff(least(CAST(CONCAT(YEAR(enddate), '-08-31') AS DATETIME),enddate),greatest(CAST(CONCAT(YEAR(enddate), '-08-01') AS DATETIME),startdate))+1,0)) AS "Aug",

SUM(GREATEST(datediff(least(CAST(CONCAT(YEAR(startdate), '-09-30') AS DATETIME),enddate),greatest(CAST(CONCAT(YEAR(startdate), '-09-01') AS DATETIME),startdate))+1,0))+SUM(GREATEST(datediff(least(CAST(CONCAT(YEAR(enddate), '-09-30') AS DATETIME),enddate),greatest(CAST(CONCAT(YEAR(enddate), '-09-01') AS DATETIME),startdate))+1,0)) AS "Sep",

SUM(GREATEST(datediff(least(CAST(CONCAT(YEAR(startdate), '-10-31') AS DATETIME),enddate),greatest(CAST(CONCAT(YEAR(startdate), '-10-01') AS DATETIME),startdate))+1,0))+SUM(GREATEST(datediff(least(CAST(CONCAT(YEAR(enddate), '-10-31') AS DATETIME),enddate),greatest(CAST(CONCAT(YEAR(enddate), '-10-01') AS DATETIME),startdate))+1,0)) AS "Oct",

SUM(GREATEST(datediff(least(CAST(CONCAT(YEAR(startdate), '-11-30') AS DATETIME),enddate),greatest(CAST(CONCAT(YEAR(startdate), '-11-01') AS DATETIME),startdate))+1,0))+SUM(GREATEST(datediff(least(CAST(CONCAT(YEAR(enddate), '-11-30') AS DATETIME),enddate),greatest(CAST(CONCAT(YEAR(enddate), '-11-01') AS DATETIME),startdate))+1,0)) AS "Nov",

SUM(GREATEST(datediff(least(CAST(CONCAT(YEAR(startdate), '-12-31') AS DATETIME),enddate),greatest(CAST(CONCAT(YEAR(startdate), '-12-01') AS DATETIME),startdate))+1,0))+SUM(GREATEST(datediff(least(CAST(CONCAT(YEAR(enddate), '-12-31') AS DATETIME),enddate),greatest(CAST(CONCAT(YEAR(enddate), '-12-01') AS DATETIME),startdate))+1,0)) AS "Dec"

from datetest

GROUP BY year(startdate)

Answer 1

所以我知道你没有使用sql-server查看你的语法，所以这个概念可能对你有用，取决于你拥有的rdbms。但是这个概念是创建一个两个日期之间差异最大的计数表，然后使用它连接到原始表并将日期范围展平为单个行，然后简单地将该信息转回。

DECLARE @Table AS TABLE (startdate DATETIME, enddate DATETIME)
INSERT INTO @Table (startdate, enddate) VALUES ('2015-12-16','2016-02-15'),('2017-01-01','2017-01-02')

;WITH cteTally as (
    SELECT MAX(DATEDIFF(day,startdate,enddate)) - 1 as Tally
    FROM
       @Table

    UNION ALL

    SELECT Tally - 1
    FROM
       cteTally
    WHERE
       Tally - 1 >= 0
)

, cteDates AS (
    SELECT
       DATEADD(day,c.Tally,t.startdate) as date
       ,YEAR(DATEADD(day,c.Tally,t.startdate)) as [Year]
       ,LEFT(DATENAME(month,DATEADD(day,c.Tally,t.startdate)),3) as [Month]
    FROM
       @Table t
       INNER JOIN cteTally c
       ON DATEDIFF(day,t.startdate,t.enddate) - 1 >= c.Tally
)

SELECT *
FROM
    cteDates
    PIVOT (
       COUNT([date])
       for [Month] IN ([Jan],[Feb],[Mar],[Apr],[May],[Jun],[Jul],[Aug],[Sep],[Oct],[Nov],[Dec])
    ) p

oracle，postgressql和sql-server支持这种类型的结构，而mysql则不支持。

计算两个日期之间每月的天数 - SQL

1 个答案: