Error when using &md

[Yegen]

I am getting an error when I use &md as follows:

data have2; set have1;
	mdCO = &md;
	do mdValid = mdCO to mdCO + &rankBack - 1;
		output;
	end;
run;

My date variable is already formatted in date9., but I am still getting the following error:

202  data have2; set have1;
203      mdCO = &md;
                -
                22
WARNING: Apparent symbolic reference MD not resolved.
ERROR 22-322: Syntax error, expecting one of the following: a name, a quoted string, a numeric constant,
              a datetime constant, a missing value, INPUT, PUT.

204      do mdValid = mdCO to mdCO + &rankBack - 1;
205          output;
206      end;
207  run;

NOTE: The SAS System stopped processing this step because of errors.

Any suggestions will be greatly appreciated! 

[Kurt_Bremser · Accepted solution]

You use macro variable md, but have never created it.

[Yegen]

I thought that it was defined, but you are right that somehow that part of the code was never included in my new code. Thanks, @Kurt_Bremser!