Seggregate a measure value based on a category

[karun_r]

I have a dataset which has a numerical column which mentions number of purchases made. Along with this, I do have the month in which the purchase is made and also the customer who did the purchase.

Now I have something like 5 years worth of data with me and I need to come up with a measure which will display how many purchases were made by each customer in each month.

So if the data is something like

 Date          Category   Purchases                  Customer

1/1/2015        A                 2                                  1

1/1/2015        B                 3                                  1

1/2/2015        A                 1                                  1

1/2/2015        B                 5                                  1

1/1/2015         A               1                                   2

I need the final output to be

Date           Purchases           Customer

1/1/2015          5                        1

1/1/2015          1                        2

1/2/2015          6                        1

I have already aggregated the purchases by month using the measure below

CALCULATE(SUM([Purchases]), FILTER(ALL(Table), ([Date]) = (MAX([Date]))))

I am using this measure inside a calculated column on the table above and this is giving me the total purchases made in a month irrespective of the customer. Now how do I further slice it down to the customer level ?