Hi all.
I have a problem to difficult to solve for me so i post my question here and hope that someone here can help me.
I have the three first columns in the table below.
I want to flag a visit with 1 if the person have had two more visits in the last 30 days.
The column Flag3VisitsLast30days is my desired output.
| PersonID | VisitID | Visitdate | Flag3VisitsLast30days |
| 1 | 1 | 2018-10-30 | 0 |
| 1 | 2 | 2018-10-01 | 1 |
| 1 | 3 | 2018-09-20 | 0 |
| 1 | 4 | 2018-09-15 | 0 |
| 1 | 5 | 2017-18-20 | 0 |
| 1 | 6 | 2016-05-10 | 0 |
| 1 | 7 | 2016-04-06 | 0 |
| 1 | 8 | 2015-01-20 | 0 |
| 2 | 9 | 2018-10-10 | 0 |
| 2 | 10 | 2017-09-08 | 0 |
| 2 | 11 | 2017-08-30 | 0 |
| 2 | 12 | 2016-05-05 | 0 |
| 2 | 13 | 2016-04-03 | 0 |
| 3 | 14 | 2018-09-01 | 0 |
| 3 | 15 | 2018-07-07 | 1 |
| 3 | 16 | 2018-06-20 | 0 |
| 3 | 17 | 2018-06-10 | 0 |
| 3 | 18 | 2017-11-15 | 0 |
| 3 | 19 | 2017-09-05 | 0 |
| 3 | 20 | 2017-08-01 | 0 |
Can anybody help me with this?
Thanks in advance.
