Selecting when criteria is met within a smaller time period

[kwokramer]

I have data for one year that includes one date variable. There are many rows per individual. I need to be able to select individuals who satisfy three criteria within any 90 day period in the year. The dates are not equally spaced or the same for every individual. Any help would be greatly appreciated. This needs to be able to done in proc sql.

[DBailey]

off the cuff...

proc sql;

select

t1.individual,

t1.datevar,

count(*) as Occurrences

from

     have t1

     inner join have t2

          on t1.individual = t2.individual

               and intck('day',t1.datevar, t2.datevar) <=90

group by t1.individual, t1.datevar

having count(*)>=3;

quit;

[Astounding]

One pitfall to code around ...

INTCK will return a negative number when the first date is later than the second date.  You probably don't want all of those included in your count.

[kwokramer]

Would sorting after the initial data pull fix that?

[DBailey]

sorting wouldn't help.

proc sql;

select

t1.individual,

t1.datevar,

count(*) as Occurrences

from

     have t1

     inner join have t2

          on t1.individual = t2.individual

               and intck('day',t1.datevar, t2.datevar) <=90

               and t2.datevar >= t1.datevar

group by t1.individual, t1.datevar

having count(*)>=3;

quit;