如何在 SQL Server 中获取给定月份范围内按月份分组的周末总天数？ [复制]

Question

如何在 SQL Server 中获取给定月份范围内按月份分组的周末（星期日）总数？

例如：所选日期：“2020 年 10 月”至“2020 年 12 月”

Month Name	Count
October	4
November	4
December	5

Answer 1

您可以使用 DATEDIFF() 和 DATENAME() 函数以及递归 CTE，例如

DECLARE @date1 AS DATE, @date2 AS DATE;
SET @date1 = '2020-10-01';
SET @date2 = '2020-12-31';

WITH cte AS 
(
  SELECT 0 AS n
  UNION ALL
  SELECT n + 1 AS value
    FROM cte
   WHERE cte.n < DATEDIFF(day,@date1,@date2) 
)
SELECT DATENAME(MONTH,DATEADD(day, n, @date1 ) ) AS [Month Name], COUNT(*) AS [Count]
  FROM cte
 WHERE DATENAME(WEEKDAY, DATEADD(day, n, @date1 ))= 'Sunday'
 GROUP BY DATENAME(MONTH,DATEADD(day, n, @date1 ))

Demo

如果日期间隔超过一年，则使用以下代码，其中也包括排序。

DECLARE @date1 AS DATE, @date2 AS DATE;
SET @date1 = '2020-10-01';
SET @date2 = '2021-03-31';

WITH cte AS 
(
  SELECT 0 AS n
  UNION ALL
  SELECT n + 1 AS value
    FROM cte
   WHERE cte.n < DATEDIFF(day,@date1,@date2) 
)
SELECT DATEPART(yy, DATEADD(day, n, @date1)) AS [Year],
       DATENAME(MONTH,DATEADD(day, n, @date1)) AS [Month Name], 
       COUNT(*) AS [Count]
  FROM cte
 WHERE DATENAME(WEEKDAY, DATEADD(day, n, @date1))= 'Sunday'
 GROUP BY DATENAME(MONTH,DATEADD(day, n, @date1)),
          DATEPART(yy, DATEADD(day, n, @date1)),
          DATEPART(m, DATEADD(day, n, @date1))
 ORDER BY [Year], DATEPART(m, DATEADD(day, n, @date1))
 OPTION (MAXRECURSION 0)

Demo