@RW9 wrote: "I have a data set that contains a datetime value that ive created from separate date and time variables and a unique identifier "IP"" Therefore: data have; input ip dt e8601dt.; new_date datalines; 123456 2017-08-21T12:01:00 123456 2017-08-26T11:00:00 ... run; This means we can run it on our machine to get data which looks like yours.  Without this we are guessing, and hence can't write tested code which accurately answers your question.  SAS is a data driven programming language, so the data is very important to any coding.   In terms of your question, step 1 would be to create a variable based on what your window is.  Maybe: data want; set have; retain base group; by ip; if first.ip=1 then do; group=1; base=dt; end; else do; if dt-base > ... then do; group=group+1; base=dt; end; end; run; So this keeps a "base" time, and changes group and base only when something goes outside the 60 minute window - how you do that check is up to you.   Hi Again.   Ok i think I see what you mean now, apologies for my knowledge on this   so if you run this code    data have; input IP DateTime DATETIME18.; datalines; 123456 31MAR18:23:58:52 123456 31MAR18:23:57:19 123456 31MAR18:23:55:46 654321 31MAR18:23:44:18 654321 31MAR18:23:35:11 run;   then it will give you some sample data that is in the same format as mine, is that was you require?   so the output of the count would be    IP           Count in 60 mins 123456             3 654321             2     Stret ... View more

@RW9 wrote: "I have a data set that contains a datetime value that ive created from separate date and time variables and a unique identifier "IP"" Therefore: data have; input ip dt e8601dt.; new_date datalines; 123456 2017-08-21T12:01:00 123456 2017-08-26T11:00:00 ... run; This means we can run it on our machine to get data which looks like yours.  Without this we are guessing, and hence can't write tested code which accurately answers your question.  SAS is a data driven programming language, so the data is very important to any coding.   In terms of your question, step 1 would be to create a variable based on what your window is.  Maybe: data want; set have; retain base group; by ip; if first.ip=1 then do; group=1; base=dt; end; else do; if dt-base > ... then do; group=group+1; base=dt; end; end; run; So this keeps a "base" time, and changes group and base only when something goes outside the 60 minute window - how you do that check is up to you.     i understand completely I wasn't myself trying to be rude I just didn't see any obvious instructions on how to do it for an amateur and don't appreciate the sarcastic comments.    I really do appreciate the help.   I'm more than happy to though ... View more

@Kurt_Bremser wrote: Excel spreadsheets are not SAS datasets, and they cannot be used to reliably represent SAS datasets (no column attributes etc). Furthermore, they can be used to transport malware, so many corporate institutions block their download. Please follow the hints contained in my footnotes. It is NOT rocket science.   Finally, I can perfectly read SAS code on my tablet without need for any special app. Hello,   I'm not sure the rudeness was warranted however I have looked at the three links in your signature and while it may not be rocket science i do not see the easy way to post the data.    This is obviously beyond my level of understanding, which I make no apologies for, I am just looking for a little assistance on something that i don't know.   Kind Regards   Stret ... View more

@Kurt_Bremser wrote: Please post an example of your data (see my footnotes for how to post data) from which your expected result is to be derived. Hi there i've attached a sample excel sheet   Apologies. ... View more