I have two column, first one being the ID of a customer and second one being the Date of purchase.
ID Date
1 2017-01-17
2 2017-01-17
3 2017-01-17
4 2017-01-17
5 2017-01-17
1 2017-01-17
7 2017-01-17
1 2017-01-17
9 2017-01-18
2 2017-01-18
3 2017-01-18
5 2017-01-18
1 2017-01-18
2 2017-01-18
I would like to summarise the Purchases
made by a Customer
at one day and create a third column that shows the amount of purchases
for the customer on that date.