You are using two level name to reference that SAS dataset, mylib.mydataset, so you will need to figure out what filename that should be.
%let libref=%scan(work.&dsn,-2,.);
%let path=%sysfunc(pathname(&libref));
%let fname=&path/%sysfunc(lowcase(%scan(&dsn,-1,.))).sas7bdat.gz;
%if %sysfunc(fileexist(&fname))%then %do;
%put Found a GZIP version of the file at &=fname ;
....
%end;
... View more
