Hello everyone, I have a data set which contains the clients ID, the days of the product consumption and the quantity consumed like this: Client_ID date consumption_days quantity Client_1 01/12/2015 28 1200 Client_1 29/12/2015 7 320 Client_1 05/01/2016 28 700 Client_2 01/02/2017 7 170 Client_2 08/02/2017 35 880 Want I want is to transform the data into weeks instead of dates, and so the quantities also would be per week as shown below: Client_ID Weeks quantity Client_1 week1 300 Client_1 week2 300 Client_1 week3 300 Client_1 week4 300 Client_1 week5 320 Client_1 week6 175 Client_1 week7 175 Client_1 week8 175 Client_1 week9 175 Client_2 week1 170 Client_2 week2 176 Client_2 week3 176 Client_2 week4 176 Client_2 week5 176 Client_2 week6 176 I tried to calculate the number of weeks of each client and the quantity consumed per week with this code: data want; set have; nb_weeks=consumption_days/7; quantity_per_week=quantity/nb_weeks; run; and then I tried many ways to transform it into weeks but it doesn't work.   Thank you in advance! ... View more