I have the following macro and sometime the variable in the where clause will exist and sometimes it won't.     %macro mem_det(tbl_, lice, sptc, type);  proc sql;   create table &tbl_ as    select distinct     ma_id     ,i_id    from data.Northwinds    where     License = "&lice"     and UPCASE(TRIM(topic_name)) in ("&sptc")     if %symexist(type) %then and Type = ("&type");    run;   quit; %mend mem_det   %mem_det(tbl_= TR_TEL_LIC, lice='LICENSED', sptc="contact", type=) /** in this instance the type isn't available **/ %mem_det(tbl_= TR_TEL_NONLIC, lice='NON-LICENSED', sptc="contact", type="FTE")   Thanks, ... View more