Need to find gap between start and end dates more than 20 days for multiple data ranges with overlaps. One Id has multiple start dates and end dates. Following Id 1 has two gaps less that 20 day. It should be considered as one range from 10/01/2012 to 10/30/2014 without any gap. 1 10/01/2012 02/01/2013 1 01/01/2013 01/31/2013 1 02/10/2013 03/31/2013 1 04/15/2013 10/30/2014 Id 2 has a gap more than 20 days between end date 01/30/2013 and start date 05/01/2013. It has to be captured. 2 01/01/2013 01/30/2013 2 05/01/2013 06/30/2014 2 07/01/2013 02/01/2014 Id 3 should be considered as one range from 01/01/2012 to 06/01/2014 without any gap. The gap between end date 02/28/2013 and start date 07/01/2013 should be ignored because range from 01/01/2012 to 01/01/2014 cavers a gap. 3 01/01/2012 01/01/2014 3 01/01/2013 02/28/2013 3 07/01/2013 06/01/2014 The cursor can do it but it works extremely slow and not acceptable. SQL fiddle http://sqlfiddle.com/#!3/27e3f/2/0