Hi All,

I wanted to be able to find the difference between two dates based on whether one criteria is the same as the criteria above it if so calculate the date difference between, if it doesnt then leave it and go to the next. Please find an example of my data set below:

e.g from my data set below - for customer id 1, row 4 would look up row 3 for customer id and because they match, it would calculate the date difference, same for row 3 to row 2, but row 2 doesnt have any data above it, it would automatically throw out a 0 against it.


A B C

Customer ID Date Amount
1 01/01/2012 20
1 02/01/2015 20
1 03/01/2016 35
3 12/12/2015 65
3 13/12/2018 12
5 23/01/2005 5
5 15/05/2007 14
12 14/02/2004 13
12 15/02/2006 8
12 16/02/2009 16
12 17/02/2012 19
13 16/05/2013 100
13 17/05/2014 120
13 18/05/2015 100


Any help would be greatly appreciated.

TIA