How to read a dataset while looping on another

[Astounding]

OK, a brand new program and a brand new approach:

proc sort data=dataset1;
   by gender ageclass;
run;

proc sort data=dataset2;
   by gender ageclass;
run;

data dataset1_revised;
   set dataset1;
   drop subset;
   rename code = assigned_code;
   output;
   output;
run;

data want;
   in1=0;
   in2=0;
   merge dataset1_revised (in=in1)  dataset2 (in=in2);
   by gender ageclass;
   if in2;
   if in1=0 then assigned_code = ' ';
run;

Doing a many-to-many merge on purpose, after expanding DATASET1 so it has double the number of observations.

[Patrick]

Nice!

I couldn't figure out how to determine in a many:many scenario if a row from a source table gets just repeated or if a new row gets read. Now you've showed me how that's done 🙂