• C

conversion from interval to decimal

i am calculating difference between two dates(datetime) declared as data type

and putting the value to decimal field
it is giving conversion type error

how to achieve this ?
santoshv25Asked:
Who is Participating?

Improve company productivity with a Business Account.Sign Up

x
 
stefan73Connect With a Mentor Commented:
Hi santoshv25,
That's a bit strange.

Oracle can do a query like this:

    EXEC SQL SELECT (sysdate-
                     to_date('01-jan-1970','dd-mon-yyyy')) * (24*60*60)
               INTO :t
               FROM DUAL;

t will now be a time_t timestamp.

So before you dive into C, check if the problem can't be solved on the DBMS side.

Cheers,
Stefan
0
 
Kent OlsenData Warehouse Architect / DBACommented:
Hi santoshv25,

Post your code.


Kent
0
 
santoshv25Author Commented:
sprintf(f_upd_qry,"update scr_ship_rec \                  
        \nset elapse_hours = case  \                      
        \n    when nc_dt is not null \                    
        \n    then \(\(nc_dt - pickup_dt\) * 24\) end");  

and elapse_hours is declared as decimal in the table
0
Build your data science skills into a career

Are you ready to take your data science career to the next step, or break into data science? With Springboard’s Data Science Career Track, you’ll master data science topics, have personalized career guidance, weekly calls with a data science expert, and a job guarantee.

 
ankuratvbCommented:
use difftime() to calc. the difference b/w 2 date-times i.e. time_t structures.

it returns the no of seconds as a double value
0
 
Kent OlsenData Warehouse Architect / DBACommented:
Hi santoshv25,

Assuming that nc_dt and pickup_dt are C variables, try this:

sprintf(f_upd_qry,"update scr_ship_rec \                  
        \nset elapse_hours = case  \                      
        \n    when nc_dt is not null \                    
        \n    then \(%d\) end", nc_dt - pickup_dt * 24);  
Kent
0
 
ankuratvbCommented:
If your date is stored in struct tm structure,use mktime to convert it to time_t.


0
 
santoshv25Author Commented:
nc_dt and pickup_dt variables are declared as type of datetime year to second

i will try the method and let u know
0
 
santoshv25Author Commented:
the logic of %d is not working
because nc_dt and pickup_dt are field variables of the table scr_ship_rec

any other solutions ?
0
 
ankuratvbCommented:
what type are they?
Are they a C date-time construct?
either time_t or struct tm.
0
 
santoshv25Author Commented:
these two fields are part of a structure in my program
under create scratch table <tablename>
{  nc_dt datetime year to second,
   pickup_dt datetime year to second
}

0
 
santoshv25Author Commented:
any ideas/solutions ?
i need this immediately.....very urgent requirement
0
 
ankuratvbCommented:
so, nc_dt and pickup_dt are variables of your own defined datetime structure?
If that is the case,you cant subtract two struct variables directly.
0
 
santoshv25Author Commented:
then ?
how to achieve this ?

2 datetime variables substraction and put the output value to a decimal field in the same table
how to achieve this ?
0
 
ankuratvbCommented:
You'll have to implement your own function to subtract each field and calc. the difference
to the resolution(minutes,seconds) you want.

You could set your values to struct tm structure and use difftime().
0
 
santoshv25Author Commented:
could u give me how to do that ?
in detail ?
0
 
ankuratvbCommented:
int main(void)
{
   struct tm time_check;
   time_t dt1;
   int year=1980, month=4, day=23;

/*  load the time_check structure with your data */
   time_check.tm_year = year - 1900;
   time_check.tm_mon  = month - 1;
   time_check.tm_mday = day;
   time_check.tm_hour = 0;
   time_check.tm_min  = 0;
   time_check.tm_sec  = 1;
   time_check.tm_isdst = -1;

/*  call mktime to fill in the weekday field of the structure */
   dt1=mktime(&time_check);

//similarly for the 2nd date
//then
   printf("Diff:%f",difftime(dt2,dt1));  
   return 0;
}
0
 
santoshv25Author Commented:
so u mean to say that the field nc_dt and pickup_dt has to be broken into year/month and day
but these will be stored as date + seconds/minutes in the field
how to break it up ?

0
 
ankuratvbCommented:
What is the format in which the date is stored in the nc_dt and pickup_dt?

You can specify the hours,minutes and seconds also in

  time_check.tm_year = year - 1900;
  time_check.tm_mon  = month - 1;
  time_check.tm_mday = day;
//from here
  time_check.tm_hour = hour;//declare hour,min,sec as int and set here
  time_check.tm_min  = min;
  time_check.tm_sec  = sec;
//to here
  time_check.tm_isdst = -1;
0
 
santoshv25Author Commented:
the format how the date is stored is :

2004-02-04 11:14:00
0
 
ankuratvbCommented:
>the format how the date is stored is :
>2004-02-04 11:14:00

IS this stored as a string(char array).
0
 
stefan73Commented:
Try NVL instead:

update scr_ship_rec
set elapse_hours = NVL((nc_dt - pickup_dt) * 24 , NULL);
0
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

All Courses

From novice to tech pro — start learning today.