compare visit time among all phases

[abraham1]

Hi Everyone!

For my study, I want to retrieve records from all phases when one hour prior to  first visit time i.e. visit_F ({HH:MM}-1) is greater than last visit time (HH:MM)

In database, all dates are stored in character format.

data visit;
input phase visit_F $20. visit_E $20.;
cards;
1 2012-04-24T19:22:03 2012-04-24T20:23:03
2 2012-04-22T07:22:03 2012-04-22T07:22:01
3 2012-04-24T19:22:03 2012-04-24T16:23:03
;
run;

[Kurt_Bremser]

Dates or times in character format are USELESS. Convert them in the database before doing anything else.

What should be the result of your data?

[s_lassen · Accepted solution]

As @Kurt_Bremser remarked, you should change the data to numeric datetimes, if possible. If not, you will have to do the conversion on the fly, e.g.:

data want;                                                                                                                              
  set visit;                                                                                                                            
  dt_first=input(visit_f,e8601dt.);                                                                                                     
  dt_last=input(visit_e,e8601dt.);                                                                                                      
  format dt_: datetime22.;                                                                                                              
  if dt_first-3600>dt_last;                                                                                                             
run;

The 3600 is (of course) the number of seconds in an hour, SAS datetime values are recorded as the number of seconds since January first, 1960.