I try to define your problem: TableX has ID and Tname TableA, TableB and TableC have ID and some_data I suggest something like data want (keep=ID some_data); merge   TableX (in=x)   TableA (in=a rename=(some_data=some_data_a))   TableB (in=b rename=(some_data=some_data_b))   TableC (in=c rename=(some_data=some_data_c)) ; by ID; if x; select (Tname);   when ('TableA') do; if a then some_data = some_data_a; end;   when ('TableB') do; if b then some_data = some_data_b; end;   when ('TableC') do; if c then some_data = some_data_c; end;   otherwise; end; run; ... View more