I have data like this:
ID relapse_Date
1 8/28/2012
1 8/30/2012
1 11/5/2012
1 1/2/2013
1 2/13/2013
1 3/18/2013
1 4/15/2013
2 5/1/2008
2 5/20/2008
2 6/14/2008
I would like to count the unique number of dates that each ID has a replase, but only count relapses that are 30 days or more apart from each other. So even though ID 1 has 7 unique relapse dates, I only want to count 5 of them (8/28/2012, 11/5/2012, 1/2/2013, 2/13/2013, 3/18/2013; the relapses on 8/30/2012 and 4/15/2013 are within 30 days of other relapse dates). I've been trying to use lag, retain, and multiple set statements but can't seem to make any of those solve my problem. Thanks in advance for any help.
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