difference between two dates

[Caro17]

Hey,

my boss wants to know how long does a therapy last. This means the difference between the start date and end date. That can be days, weeks or months. The format is ddmmmyy:hh:mm:ss. And he wants to see the days, weeks and months of the therapy.

How can I solve this?

Caro

[Shmuel]

According to format you have a daytime variably.

You can get the date using function datepart(<daytime variable>);

Having two dates calculate:

- days = date2 - date1;

- months = intck('month', date1, date2);

- weeks can be calculated as days/7 or by using intck('week', date1, date2);

[Caro17]

With the days I get between 0 and 31536000 days. That means there must be also weeks and months. But I get nothing with weeks and months.

data datdif
set therapy
start = datepart(start);
end = datepart(end);
run;

data datdif;
set therapy
days = end - start;
run;

proc freq data = datdif; tables days; run;

data datdif;
set therapy;
weeks = intck('week', start, end);

proc freq data = datdif; tables weeks; run;

data datdif;
set therapy;
months = intck('month', start, end);

proc freq data = datdif; tables months; run;

[Shmuel]

Do it all in one step:

data datdif
set therapy
start = datepart(start);
end = datepart(end);
days = end - start;
weeks = intck('week', start, end);
months = intck('month', start, end);
run;

proc freq data = datdif; 
  tables days weeks months; 
run;

[ballardw · Accepted solution]

Is your date a actual SAS datetime variable or something character?

You may also want to provide some example of what your data looks like.

The SAS INTCK function will return the number of intervals between two SAS date, time or datetime variables

You could get the number of days between two datetime values with

days = intck('dtday',firstdt, seconddt)

weeks =intck('dtweek',firstdt, seconddt)

months=intck('dtmonth',firstdt, seconddt)

but the values would have to be SAS datetime values.

Or use dates and the interval in the function of 'day' 'week' or 'month'