Automatically filling out control table with numeric values for loop-job (user written code)

[TurnTheBacon]

I've created a loop-job which runs the inner job once per month, from the previous month and back until october 2011. The job is parameterized so that -1 indicates one month back, -2 indicates two months back, etc. The control table currently contains the variable "month_back" with values from 1- to -13, so that the inner job is run from oct2012 to oct 2011.

My problem is that the values in the control table are static, so each month I have to manually add another number so that it goes all the way back to oct2011.

What I need is user written code that creates a table where month_back is automatically filled out with all the proper values according to the current month. If I run it today it should get values from -1 to -13, if I run it next month it should get values from -1 to -14, etc.

I'd appreciate any advice on how to accomplish this.

Basic start:

data work.months_back;

     %let startdate = %sysfunc(intnx(month, %sysfunc(date()), -1, E), date9.); *appears as 31OCT2012 if run in November;
     month_back = -1 *one month back;

     *must get values for all months back until october 2011;

run;

data &_output;

     set months_back;

run;

[RichardinOz · Accepted solution]

I think this is what you are looking for.  Day of month in these dates does not matter.

%Let initmonth = '01OCT2011'D ;

Data control ;

    Thismonth = date() ;

    Intervals = 1 + intck ('MONTH', &initmonth, thismonth) ;

    Put intervals= ;

    Do month_back = -1 to -intervals by -1 ;

        Output ;

    End ;

    Keep month_back ;

Run ;

Richard in Oz

[TurnTheBacon]

Brilliant, thanks.