How to add multiple date ranges to find the total time period in number of years , months and days
4/12/2015 to 6/2/2019 = 4 years,1 months,21 days
9/8/2010 to 1/8/2012 = 1 years,4 months,0 days
5/3/2007 to 3/4/2008 = 0 years,10 months,1 days
3/5/2004 to 4/3/2006 = 1 years,10 months,1 days...