Hello,   I'm stuck on a problem here that I hope there is a solution for somewhere in the SAS-commands. The data looks like this:     The raw-data consists of number of cars arriving at a certain location. There is a file when they arrive (this one) and one when they leave. The data of interest is datum (date), timme (hour) and freq ) sum of number of cars arriving during that hour that date.   In the raw-data there might be some hours certain days when no cars arrive, as you can see above (hour 0, 09/02/2015 for example). I need to match this file with the other to get the total sum of cars present every hour, taking the sum of arriving cars and subtract the leaving.   Problem is I need to have rows even when there are 0 cars arriving, not a missing row like seen above.   Is there any way I can make a loop or something similar to check if there are rows for every hour (0-23), every day (whole 2015). If the row is missing SAS will add the row with the date and hour missing with FREQ=0. Is this possible?   Regards Peter Karlsson ... View more