set serveroutput on; declare a varchar(20); begin a:='Hello'; dbms_output.put_line(a); end; /
Standard input is empty
Standard output is empty
Error: near line 1: near "set": syntax error Error: near line 2: near "declare": syntax error Error: near line 3: near "a": syntax error Error: near line 5: near "dbms_output": syntax error Error: near line 6: cannot commit - no transaction is active