@steve-2 - thanks for replying. But your query gives me a different result. Your query gives me the number of TIMES custA's status was changed (Ex: custA status1, numdays = 2 - custA's status was updated to 1 twice. But, what I want is CustA has status 1 for ((01/01/2013 - 01/05/2013 = 4 days) + (01/20/2013 - 02/01/2013 = 11 days)) = 15 days.

@dgowrij - thanks for replying. But your query gives me a different result. For example,CustA was present in status 2 for 15 days (01/20/2013 - 01/05/2013), but your query gives me 30 days.