Date Format

[Toni2]

I have spent hours on this and i am still struggling to figure out the issue 

For some reason SAS doesn't recognise the comparison "if date>=31/01/98" even though i have already formatted date variable. The outcome for variable test is always 1  even for dates prior to 31/01/98

Any help would be appreciated ?  

data b;
informat date anydtdte12.;
set a;
format date ddmmyy8.;
run;

data c;
set b;
if date>=31/01/98 then test = 1;else test=0;
run;

Obs	date	test
1	31/01/1997	1
2	28/02/1997	1
3	31/03/1997	1
4	30/04/1997	1
5	31/05/1997	1
6	30/06/1997	1
7	31/07/1997	1
8	31/08/1997	1
9	30/09/1997	1
10	31/10/1997	1
11	30/11/1997	1
12	31/12/1997	1
13	31/01/1998	1
14	28/02/1998	1
15	31/03/1998	1
16	30/04/1998	1
17	31/05/1998	1
18	30/06/1998	1
19	31/07/1998	1
20	31/08/1998	1
21	30/09/1998	1
22	31/10/1998	1
23	30/11/1998	1
24	31/12/1998	1
25	31/01/1999	1

[PaigeMiller · Accepted solution]

31/01/98 is not a date, even if it looks like one to you. It is 31 divided by 01 divided by 98.

What you really want is

if date>='31JAN1998'd then test = 1;else test=0;

Also, this is not a FORMAT issue, it doesn't matter what format is assigned to variable DATE.

[Toni2]

thank you!

[Kurt_Bremser]

And if you do not like the DATE9 format used in SAS date literals, use the INPUT function:

if date >= input("31/01/1998",ddmmyy10.)
then test = 1;
else test = 0;

And do not use 2-digit years, unless you like to be bitten in the behind by your own code sooner or later.

[Toni2]

thank you quite useful! 🙂