sql – 合并重叠的日期间隔

是否有更好的方法来合并重叠的日期间隔？
我提出的解决方案非常简单,现在我想知道其他人是否能更好地了解如何做到这一点.

/***** DATA EXAMPLE *****/
DECLARE @T TABLE (d1 DATETIME,d2 DATETIME)
INSERT INTO @T (d1,d2)
        SELECT '2010-01-01','2010-03-31' UNION SELECT '2010-04-01','2010-05-31' 
  UNION SELECT '2010-06-15','2010-06-25' UNION SELECT '2010-06-26','2010-07-10' 
  UNION SELECT '2010-08-01','2010-08-05' UNION SELECT '2010-08-01','2010-08-09' 
  UNION SELECT '2010-08-02','2010-08-07' UNION SELECT '2010-08-08','2010-08-08' 
  UNION SELECT '2010-08-09','2010-08-12' UNION SELECT '2010-07-04','2010-08-16' 
  UNION SELECT '2010-11-01','2010-12-31' UNION SELECT '2010-03-01','2010-06-13' 

/***** INTERVAL ANALYSIS *****/
WHILE (1=1)  BEGIN
  UPDATE t1 SET t1.d2 = t2.d2
  FROM @T AS t1 INNER JOIN @T AS t2 ON 
            DATEADD(day,1,t1.d2) BETWEEN t2.d1 AND t2.d2 
  IF @@ROWCOUNT = 0 BREAK
END

/***** RESULT *****/
SELECT StartDate = MIN(d1),EndDate = d2
FROM @T
GROUP BY d2
ORDER BY StartDate,EndDate

/***** OUTPUT *****/
/*****
StartDate   EndDate
2010-01-01  2010-06-13 
2010-06-15  2010-08-16 
2010-11-01  2010-12-31 
*****/

解决方法

Packing Date Intervals还有另一个帖子.

我用各种日期范围测试了这个,包括这里列出的日期范围,每次都能正常工作.

SELECT 
       s1.StartDate,--t1.EndDate 
       MIN(t1.EndDate) AS EndDate
FROM @T s1 
INNER JOIN @T t1 ON s1.StartDate <= t1.EndDate
  AND NOT EXISTS(SELECT * FROM @T t2 
                 WHERE t1.EndDate >= t2.StartDate AND t1.EndDate < t2.EndDate) 
WHERE NOT EXISTS(SELECT * FROM @T s2 
                 WHERE s1.StartDate > s2.StartDate AND s1.StartDate <= s2.EndDate) 
GROUP BY s1.StartDate 
ORDER BY s1.StartDate

结果是：

StartDate  | EndDate
2010-01-01 | 2010-06-13
2010-06-15 | 2010-06-25
2010-06-26 | 2010-08-16
2010-11-01 | 2010-12-31

（编辑：安卓应用网）

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