N months from a give yyyymmdd date? 1

[Dan01]

Hi, does someone have an example on how to, say, get a yyyymmdd 9 months prior to 20010301? Thanks, Dan.

 

[k5tm]

Please specify operating system and compiler. (I ahve looked at some of your previous posts, to no avail.) Some compilers are more advanced than others...
Tom Morrison

 

[Dan01]

Thank Tom. Hewlett-Packard COBOL II, includes $POST85 for Cobol 85 uses. Dan.

 

[k5tm]

Dan, it depends on your definition of 9 months. If 9 months equals 270 days, then use INTEGER-OF-DATE intrinsic function to get an integer value, subtract 270, and use DATE-OF-INTEGER on the result. (273 or 274 would be a closer estimate of 9 months.)

If 9 months means "same day of month, none months earlier" then one would subtract 9 from the month value, with appropriate borrow from the year value, and a fixup for day-of-month in the range 29-31.

So, what are the business rules?
Tom Morrison

 

[Dan01]

It would be nine months earlier, same day of the month. Thanks, Dan.

 

[Dan01]

Tom, if you have sample code, that would be great. Thanks in advance. Dan.

 

[k5tm]

Okay, Dan. Here is a skeleton. I am leaving several things to you (such as leap year, making sure your date is valid to begin with, etc), but this is a start:

in DATA DIVISION:

01  DATE-TO-CHANGE.
    03  YYYY   PIC 9(4).
    03  MM     PIC 99.
        88  VALID-MONTH values 1 thru 12.
    03  DD     PIC 99.

01  VALUE "312831303130313130313031".
    03  DAYS-IN-MONTH  PIC 99 OCCURS 12.

in PROCEDURE DIVISION, after making sure that DATE-TO-CHANGE contains a valid numeric date (example for 9 months):

    IF MM < 10
        ADD 3 TO MM
        SUBTRACT 1 FROM YYYY
    ELSE
        SUBTRACT 9 FROM MM
    END-IF.
    IF DD > DAYS-IN-MONTH (MM)
        MOVE DAYS-IN-MONTH (MM) to DD
    END-IF.

Happy coding!

Tom Morrison

 

[Dan01]

Thanks Tom, most kind of you. Dan.

 

[taasarge]

I would simply include a query using the sysdummy1 table to get the date.

Select current date - 9 months
from sysibm.sysdummy1

Let DB2 or your sql deal with it....