Merge overlapping date intervals

Question

Is there a better way of merging overlapping date intervals?
The solution I came up with is so simple that now I wonder if someone else has a better idea of how this cou

Answer 1

I was looking for the same solution and came across this post on Combine overlapping datetime to return single overlapping range record.

There is another thread on Packing Date Intervals.

I tested this with various date ranges, including the ones listed here, and it works correctly every time.

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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 

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The result is:

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