I am a beginner in timeseries, I have two datatables with different dates and i'd like to have one datatable with all the dates and the sum of the quantitative value ( money paied by the company), for example I have :
here is the first datatable with the price paied
and i'd like to have this one :
date         old_price      new_price
02/03/2015     1,7+1,2       5,7+1,7
05/05/2015      5,7+1,7       5,7+2,5
20/08/2015      5,7+2,5       2,3+2,5
08/09/2015       2,3+2,5       2,3+4,7
Thank you very much for your help !
 
     
    