SQL>
SQL> SET ECHO ON
SQL> SET SERVEROUTPUT ON
SQL> DECLARE
2 a VARCHAR2(30);
3 b VARCHAR2(30);
4 c VARCHAR2(30);
5 BEGIN
6 a := ' AAA ';
7 b := ' BBB ';
8 c := a || b;
9 DBMS_OUTPUT.PUT_LINE(c);
10 END;
11 /
AAA BBB
PL/SQL procedure successfully completed.
SQL>