Hello,

i have a dataset of around 900,000 observations from about 130,000 ids. The variables i am working with are mostly dates. i wanted to take just the first event date that happened during 1 year period after the interview date. Some of the dates recorded can come from the events that happened before the interview date.

my data would look like this
ID intdate effdate1 effdate2 effdate3 dureffdate1 dureffdate2
1 8/01/2010 28-Apr-10 28-Jul-11 110 566
2 30/08/2010 20-Dec-11 477
3 6/01/2010 31-Jul-10 206
4 13/01/2010 16-Apr-10 93
5 4/08/2010 27-Jul-10 14-Apr-11 -8 253
6 11/03/2010 22-Dec-10 286
7 20/10/2010 23-Sep-10 -27
8 3/11/2010 8-Dec-11 400
9 16/06/2010 6-Sep-11 447
10 29/06/2010 6-Dec-10 25-Jan-11 160 210
11 1/11/2010 6-Oct-11 339
12 15/02/2010 9-Aug-10 175
13 12/11/2010 27-Sep-11 319
14 2/02/2010 10-Mar-11 401
15 14/02/2010 8-Aug-11 540
from intdate and effdate1 to 8 i calculated the interval which resulted in dureffdate1 to 8

i wanted to take just the first date of event which happened during 1 year period after intdate.
how do i do that without deleting other observations as i need them for other analysis.

thank you