I'm not well versed in SAS language, just enough to get by with basic logic in regards to data and proc sql steps, maybe a sort here and there. Hoping for some direction on a problem I'm facing. Dataset DATE CUST_ID SYSTEM COLOR 3/31/2021 15 ORA BLUE 4/30/2021 13 ORA BLUE 5/31/2021 10 ORA BLUE 6/30/2021 19 ORA BLUE 7/31/2021 11 ORA BLUE 8/31/2021 14 ORA BLUE 9/30/2021 21 ORA BLUE 10/31/2021 16 ORA BLUE 11/30/2021 12 ORA BLUE 12/31/2021 17 ORA BLUE 1/31/2022 22 ORA BLUE 2/28/2022 18 ORA BLUE 3/31/2022 20 SIS UNK 4/30/2022 23 SIS UNK   The issue: When a customer switches to another system their color data goes missing. Hence the return value of unknown. What I need assistance in is coming up with the right logic to assign the unknown fields to the last known value. Now it doesn't have to be the last known value as theoretically the color should never change once set, until it loads into another system.   So the dataset I want to return is: DATE CUST_ID SYSTEM COLOR 3/31/2021 15 ORA BLUE 4/30/2021 13 ORA BLUE 5/31/2021 10 ORA BLUE 6/30/2021 19 ORA BLUE 7/31/2021 11 ORA BLUE 8/31/2021 14 ORA BLUE 9/30/2021 21 ORA BLUE 10/31/2021 16 ORA BLUE 11/30/2021 12 ORA BLUE 12/31/2021 17 ORA BLUE 1/31/2022 22 ORA BLUE 2/28/2022 18 ORA BLUE 3/31/2022 20 SIS BLUE 4/30/2022 23 SIS BLUE   Thanks for your help in advance! ... View more