The Macro language is powerfull, but sometimes it would be nice if you could avoid making a macro, just to make a small part of your code conditional. For example: when your program should delete a tabel - but only if it exist (to avoid warnings in the log).
%put Warnings if you drop a a table that doesnt exist;
proc sql ;
drop table WORK.CLASS;
quit;
options mprint;
%put Method 1 (Old school): wrap the code in a macro deleting the table if it exists - call macro;
%macro mymacro;
%if %sysfunc(exist(WORK.CLASS)) %then
%do;
proc sql ;
drop table WORK.CLASS;
quit;
%end;
%mend;
%mymacro;
***Same but simpler (no macro definition) using SAS function IFC.;
%put Method 2: use IFC - avoid new macro;
proc sql ;
%sysfunc(IFC(%sysfunc(exist(WORK.CLASS)), drop table WORK.CLASS, )); ;
quit;
Also with SAS 9.4 Maintenance 5 You can now use %IF-%THEN-%ELSE constructs in open code
https://blogs.sas.com/content/sasdummy/2018/07/05/if-then-else-sas-programs/
%put Method 3: SAS 9.4M5 only - use in open code;
%if %sysfunc(exist(WORK.CLASS)) %then
%do;
proc sql ;
drop table WORK.CLASS;
quit;
%end;
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