Find date difference by multiple groups

[deep3]

Hi,

I have dataset as below. For each id, i am trying to find days difference between the last activity reported and first sale. 

activitytype     id      date           datediff

activity            1     01-Jan-20

activity            1     01-Jan-20

activity            1     08-Jan-20

sale                1     01-Feb-20      24

activity            2     01-Jan-20

sale                2      05-Jan-20      4

activity            2     08-Jan-20

sale                2     10-Feb-20      33

Initially i tried spliting the data into activity to get last.activity by id and  sale to get first.sale by id. but this is leaving out row 6 and row 7. code I tried is below. Please suggest

/*sale dataset */

by id;
if first.id then flag = 2;

/*activity dataset */

by id;
if last.id then flag = 1;

[PaigeMiller]

UNTESTED CODE

data want;
    set have;
    prev_id=lag(id);
    prev_activitytype=lag(activitytype);
    prev_date=lag(date);
    if id=prev_id and activitytype='sale' and prev_activitytype='activity'
        then datediff=date-prev_date;
    drop prev_:;
run;

If you want tested code, you would need to provide your data as actual SAS data step code, following these instructions: https://blogs.sas.com/content/sastraining/2016/03/11/jedi-sas-tricks-data-to-data-step-macro/

[Ksharp]

data have;

 set have;

if lag(activitytype)='sale' then group+1;

run;

proc sql;
create table want as
select * , range(date) as date_diff
from have
group by group;
quit;