case when from the data step

[Babloo]

Appreciate if someone of you help me to write the 'case when ...' statement to derive the variable 'KHIREF' from the following data step?

data  WORK.INSURANCE_POLICY_0002(drop=POLICY_NO checkdigit x_source_system_cd);
  set  WORK.INSURANCE_POLICY_0002;
  format checkdigit z2.;
if POLICY_NO ^= '' then do;     
/* combine source code and policy number */
khiref=substr(left(x_source_system_cd),2,1)!!substr(left(policy_no),1,2)!!substr(left(policy_no),4,7);
/* calculate the checkdigit modulo 97. replace 0 by 97 */
checkdigit=compress(mod(khiref,97));
if checkdigit=0 then checkdigit=97;
/* add the checkdigit */
khiref=substr(left(khiref),1,10)!!vvalue(checkdigit);
end;
run;

Sample data as follows:

data WORK.INSURANCE_POLICY_0002;
/*length POLICY_NO $20.;*/
POLICY_NO='94_0006288';
run;

[Kurt_Bremser]

Your data step needs fixing:

32         data  WORK.INSURANCE_POLICY_0002(drop=POLICY_NO checkdigit x_source_system_cd);
33           set  WORK.INSURANCE_POLICY_0002;
34           format checkdigit z2.;
35         if POLICY_NO ^= '' then do;
36         /* combine source code and policy number */
37         khiref=substr(left(x_source_system_cd),2,1)!!substr(left(policy_no),1,2)!!substr(left(policy_no),4,7);
38         /* calculate the checkdigit modulo 97. replace 0 by 97 */
39         checkdigit=compress(mod(khiref,97));
40         if checkdigit=0 then checkdigit=97;
41         /* add the checkdigit */
42         khiref=substr(left(khiref),1,10)!!vvalue(checkdigit);
43         end;
44         run;

NOTE: Numeric values have been converted to character values at the places given by: (Line):(Column).
      37:20   39:21   
NOTE: Character values have been converted to numeric values at the places given by: (Line):(Column).
      39:12   39:25   
NOTE: Variable x_source_system_cd is uninitialized.

Given the necessary intermediate steps, I'd recommend to stay with the data step, it's easier to read and maintain for such kind of logic.

[Babloo]

I have to implement this logic in DI studio and I was asked to use only
'case when'

[Rick_SAS]

See the blog post "The SELECT statement in the SAS DATA step."