Proc BranchTo

From sasCommunity

Proc BranchTo allows users to write conditionally executed code based on a logical expression.

Syntax:

Proc BranchTo select = (<logical expression>)
              WhenTrue  do;
                        *true statements here;
                        end;
              WhenFalse do;
                        *false statements here;
                        end;
              otherwise do;
                        *missing statements here;
                        end;

Usage:

%Let Libname = sashelp;
%Let Memname = Class;

Proc SQL noprint;
         select Nobs 
         into  :Nobs
         from   Dictionary.Tables
         where  Libname eq "%upcase(&Libname.)"
           and  Memname eq "%upcase(&Memname.)"
           and  Memtype eq 'DATA';
         quit;

Proc BranchTo select =  &Nobs.
              WhenTrue  do;
                        Proc Freq data = &Libname..&Memname.;
                        end;
              WhenFalse do;
                        %Put Note3: eh?! no data!;
                        end;
              otherwise do;
                        *missing statements here;
                        end;
run;

Unfortunately, this does not work. That's because there is no PROC BRANCHTO. The "information" above follows a tradition in the SAS user community of occasionally offering advice which is not intended to be taken seriously. See, for example, Programming for Job Security: Maximize Your Indispensability - Become a Specialist.

PROC BRANCHTO can be emulated, however. One approach is to use the CALL EXECUTE statement in a DATA step. Continuing the example above, the code would be:

data _null_;
select ( abs( sign(&Nobs) ) );
   when (1)  call execute('Proc Freq data = &Libname..&Memname.; run;');
   when (0)  call execute('%nrstr(%Put NOTE: eh?! no data!       ;)  ');
   otherwise call execute('%nrstr(%Put NOTE: HOW DID WE GET HERE?;)  ');
   end;
run;