Subtracting 2 dates in large data set

[jos283]

As part of a large data set, 2 of my columns contain dates that I want to subtract to get the difference in number of days

For example (imagine 1000+ rows):

Person         Column B     Date_Start    Date_End    Column E

   A                                        1/1/17          1/9/17

   B                                        3/3/17          3/6/17

   C                                        2/7/17          2/12/17

   D                                        8/8/17          8/8/17

   E                                        9/1/17          9/30/17

How do I subtract Date_End from Date_Start columns to get:

Date_Difference

           8

           3

           5

           0

          29

I've tried proc sql where I've assigned the following, but this doesn't seem right:

     min(Date_Start) as Date_Start,
     max(Date_End) as Date_End,
     max(Date_End) - min(Date_Start) as Date_Difference,

 Also had a go with (preferred code layout):

data timing;
set timing;
by Person;
   Date_Difference = intck('Date_Difference', Date_Start, Date_End);
   put Date_Difference = ;
run;

Any help with the coding would be appreciated!

[kiranv_ · Accepted solution]

  select Date_End - Date_Start as Date_Difference,

the above code should work

[Reeza]

Dates can be subtracted directly to get the number of days, either in SQL or the data step. If you're going to use INTCK, the interval, which is the first parameter is 'DAY'

[Astounding]

If your dates are actually character strings rather than true SAS dates, you would need:

data want;

set timing;

date_difference = input(Date_End, mmddyy8.) - input(Date_Begin, mmddyy8.);

run;