Question

如果连续日期是昨天，我想从我的假期表中过滤连续日期。下面是我的代码，用于获取行号的连续日期。

SELECT 
    RW = ROW_NUMBER() OVER( PARTITION BY GRP ORDER BY HolidayDate),
    HolidayDate
FROM
    (SELECT 
         HolidayDate, 
         DATEDIFF(Day, '1900-01-01', HolidayDate) - ROW_NUMBER() OVER (ORDER BY HolidayDate) AS GRP, 
         HolidayType
     FROM 
         Holiday) A
ORDER BY
    HolidayDate

例如，昨天的日期是2017年3月14日。如果涉及此日期的任何连续假期，我需要从Holiday表中获取数据。

如果没有匹配则输出应为null，否则它应显示如下日期

03/12/2017
03/13/2017
03/14/2017

Answer 1

嗯，你快到了！

定义＆＃34;昨天＆＃34;作为参数，因为它很容易找到。

CREATE TABLE Holiday(
    HolidayDate SMALLDATETIME PRIMARY KEY, 
    HolidayType VARCHAR(20)
);

INSERT INTO Holiday VALUES 
  ('2016-12-25', 'A'), ('2016-12-26', 'A'), ('2017-01-01', 'A'), 
  ('2017-04-12', 'A'), ('2017-04-13', 'A'), ('2017-04-14', 'A');

DECLARE @yesterday SMALLDATETIME;
SET @yesterday = '2017-04-13'; -- belongs to a group of consecutive holidays
-- SET @yesterday = '2017-01-01'; -- isolated holiday
-- SET @yesterday = '2017-02-10'; -- not a holiday

; WITH groups as 
(
SELECT 
    HolidayDate, 
    DATEDIFF(Day, '1900-01-01', HolidayDate) 
    - ROW_NUMBER() OVER (ORDER BY HolidayDate) AS GRP, 
    HolidayType
FROM Holiday
),
consecutive as (
    SELECT GRP FROM groups GROUP BY GRP HAVING COUNT(*) > 1
)
SELECT DISTINCT g2.HolidayDate, g2.HolidayType 
FROM consecutive c 
JOIN groups g1 ON c.GRP = g1.GRP 
JOIN groups g2 ON g1.GRP = g2.GRP
WHERE g1.HolidayDate = @yesterday;

过滤SQL Server中的连续日期

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