I have a problem with the SOM.ALS (SUMIF function in English) function. I have a very large file of numbers, this is a small part of it. If want to know the total amount of days a customer has stayed in a hotel. But some customers have stayed for multiple days (customer 1 has stayed 2 times, 30 days in total). How do I create a formule that I can add up the days in the hotel, dependent on the customer number.
If now use this: SOM.ALS(A2:A6900; "1"; F2:F6900), but then I have to manually chance the criterium each time.