How to deduct an hour from the TIME20.3 format?

[bd_user_10]

I need to deduct an hour from my Time variable. Currently, the variable is in TIME20.3 format. 

Here is an example, 

Time                                           

10:07:46.104                 

and i need 

Time_new

9:07:46.104

Also, i would like to create another time variable as

Time_new2

9:07:46.000

Thanks in advance for your help. 

[Tom]

Time values are stored as the number of seconds since midnight.  To to subtract one hour you need to subtract 60*60 seconds.

It is easier to just use a time literal.  '01:00't is one hour.

data test;
  have = '10:07:46.104't ;
  want = have - '01:00't ;
  format have want time20.3 ;
  put have= want=;
run;

Do you want to round the time to the newest second?  ROUND(want,1)

Or truncate the fractional seconds? INT(want)

[Sajid01]

Internally SAS maintains time as number of seconds from midnight. So one hour is 3600 Seconds.
Subtracting 3600 gives the result.
Sample code is given below. Modify as needed

data test_time;
informat time_ time12.3;
format time_ time12.3;
input time_;
datalines;
10:07:46.104   
12:00:16.100  
02:11:26.040  
;
run;
data test_time;
format new_time time12.3;
set test_time;
new_time=time_ - 3600;
run;

The output will be some thing like this.
Time_ is the original time and new_time is what we get substracting one hour (3600 secs)

Obs	new_time	time_
1	9:07:46.104	10:07:46.104
2	11:00:16.100	12:00:16.100
3	1:11:26.040	2:11:26.040

[sbxkoenk · Accepted solution]

Hello,

As mentioned by @Tom and @Sajid01 the format does not play a role w.r.t. your question.

You can also use the INTNX function to get what you want.

data _NULL_;
 have = '10:07:46.104't ;
 Time_new  = INTNX('HOUR',have,-1,'SAME');
 put Time_new  TIME20.3;
 Time_new2 = INTNX('SECOND',have,-60*60,'BEGINNING');
 put Time_new2 TIME20.3;
run;
/* end of program */

Cheers,

Koen