https://communities.sas.com/t5/SAS-Procedures/Minus-first-obs-with-second-obs/m-p/48922#M13257 In a dataset i have two variables id,sal now i want the first observation of id should be minused from another observation i.e second observation of sal like that Tue, 23 Sep 2008 06:44:55 GMT R_Win 2008-09-23T06:44:55Z https://communities.sas.com/t5/SAS-Procedures/Minus-first-obs-with-second-obs/m-p/48922#M13257 In a dataset i have two variables id,sal now i want the first observation of id should be minused from another observation i.e second observation of sal like that Tue, 23 Sep 2008 06:44:55 GMT https://communities.sas.com/t5/SAS-Procedures/Minus-first-obs-with-second-obs/m-p/48922#M13257 R_Win 2008-09-23T06:44:55Z https://communities.sas.com/t5/SAS-Procedures/Minus-first-obs-with-second-obs/m-p/48923#M13258 I believe that this has already been answered in a previous thread of yours...?<BR /> <BR /> /Linus Tue, 23 Sep 2008 12:30:17 GMT https://communities.sas.com/t5/SAS-Procedures/Minus-first-obs-with-second-obs/m-p/48923#M13258 LinusH 2008-09-23T12:30:17Z