https://communities.sas.com/t5/SAS-Procedures/Date-comparison/m-p/62565#M17792 I have data that has service-from and service-to dates. If all of the dates for a particular client are unique, I want to delete them, however, if there is any overlap, I need to keep them. One way that I thought of was to create an array, but I'm not good with those. Any other suggestions? Fri, 21 Nov 2008 14:27:15 GMT deleted_user 2008-11-21T14:27:15Z https://communities.sas.com/t5/SAS-Procedures/Date-comparison/m-p/62565#M17792 I have data that has service-from and service-to dates. If all of the dates for a particular client are unique, I want to delete them, however, if there is any overlap, I need to keep them. One way that I thought of was to create an array, but I'm not good with those. Any other suggestions? Fri, 21 Nov 2008 14:27:15 GMT https://communities.sas.com/t5/SAS-Procedures/Date-comparison/m-p/62565#M17792 deleted_user 2008-11-21T14:27:15Z https://communities.sas.com/t5/SAS-Procedures/Date-comparison/m-p/62566#M17793 If your data has one service-from/to pair on each observation, and the dates is all you want to keep, my suggestion is to sort your data in client and service-from (and service-to if necessary) order. <BR /> Then use RETAIN or LAG() to compare the current service-from with previous service-tom date. If overlap output the columns you want to keep.<BR /> <BR /> Regards,<BR /> Linus Fri, 21 Nov 2008 15:22:06 GMT https://communities.sas.com/t5/SAS-Procedures/Date-comparison/m-p/62566#M17793 LinusH 2008-11-21T15:22:06Z