Separating dataset

[learn2]

I have a dataset as shown in Table 1. I want to separate this dataset into two datasets made up of only Previous visits for each of the IDs present, and another dataset for only the visits after the index date for each ID. It’s important to have all ids whether they had a visit or not so each ID can be compared in the previous vs after phases of treatment. A little stumped on how to go about this, any help would be appreciated!

Table 1:

ID	Visit date	Index date	Previous visits label	After index label
1	.	Jun7,2005	.	.
2	Jan3,1999	Apr8,1999	1	0
3	Jan3,1999	Jan1,1998	0	1
4	Oct7,2002	Sept10,2001	0	1
4	Jun1,2001	Sep10,2001	1	0

Wanted datasets:

Dataset A (Previous visits)

ID	Visit date	Index date	Previous visits label
1	.	Jun7,2005	.
2	Jan3,1999	Apr8,1999	1
3	.	Jan1,1998	.
4	Jun1,2001	Sep10,2001	1

 Dataset 2 (After index visits)

ID	Visit date	Index date	After index label label
1	.	Jun7,2005	.
2	.	Apr8,1999	.
3	Jan3,1999	Jan1,1998	1
4	Oct7,2002	Sep10,2001	1

[Ksharp · Accepted solution]

Assuming I understand your question.

data have;
input ID
Visitdate : $20.
Indexdate : $20.
Previousvisitslabel	
Afterindexlabel ;
cards;
1
.
Jun7,2005
.
.
2
Jan3,1999
Apr8,1999
1
0
3
Jan3,1999
Jan1,1998
0
1
4
Oct7,2002
Sept10,2001
0
1
4
Jun1,2001
Sep10,2001
1
0
;
run;
proc sql;
create table A as
 select id,' ' as Visitdate,Indexdate,. as Previousvisitslabel from have
  where id not in (select id from have where Previousvisitslabel=1)
 union all
  select ID,
 Visitdate ,
Indexdate, 
Previousvisitslabel from have where Previousvisitslabel=1
order by id ;
  
  
  
create table B as
 select id,' ' as Visitdate,Indexdate,. as Afterindexlabel from have
  where id not in (select id from have where Afterindexlabel=1)
 union all
  select ID,
 Visitdate ,
Indexdate, 
Afterindexlabel from have where Afterindexlabel=1
order by id ;  
quit;