Hi, I have a data set such as the following, with date format YYMMDD10:   ID Date Count -5 days 004 01/11/2016 0 007 2011/03/10 0 007 2012/12/04 0 007 2012/12/05 1 007 2012/12/05 2 007 2012/12/07 3 008 2012/10/01 0 008 2012/10/04 1 010 2014/11/25 0 010 2015/04/19 0 010 2015/04/20 1   I want to count how many times the ID variable occurs within -5 days, or potentially +/-5 days.   Any help would be really appreciated.   Thanks ... View more