Say you have Group A and allow the user to select a start and end date for that group. You also have Group B but you only allow the user to pick a start date and calculate the end date based upon the number of days between Group A.
For example:
Group A Start - 1/1/2014 (user selected)
Group A End - 1/20/2014 (user selected)
Group B Start - 1/1/2013 (user selected)
Group B End - 1/20/2013 (calculated)
So, if you were to make a line chart from this using the date as the dimension and comparing Group A to Group B it would work just fine because you can take off a year in the expression and the dates on the x-axis start at January 1 and they have the same number of days. Or, use something like Week Number as the dimension. No problem.
But say you were to change 'Group B Start' to something off kilter like 3/4/2013.
Group B Start - 3/4/2013 (user selected)
Group B End - 3/24/2013 (calculated)
The calculated 'Group B End' ensures you'll be comparing the same amount of days on the line chart but how do you get 1/1/2014 to line up with 3/4/2013 on the x-axis so you can visually compare the same 20 days? In other words, I want to align the ordinal number of the result set.
1/1/2014 & 3/4/2013 is ordinal 1.
1/2/2014 & 3/5/2013 is ordinal 2.
etc.
1/20/2014 & 3/24/2013 is ordinal 20.
