A number of functions allow you to either add (PAD) or remove (TRIM) characters to an existing string.
LPAD/LTRIM do it from the left side of the string.
RPAD/RTRIM from the right side.
TRIM function allows you to select the trimming mode:
Syntax
v_tx:= lpad(string,length,extra string);
v_tx:= ltrim(string [,character]);
v_tx:= trim(LEADING|TRAILING|BOTH character from string);
SQL> SQL> declare-- from ww w.j a v a 2 s .c o m 2 v1_tx VARCHAR2(20):='Hello!'; 3 v2_tx VARCHAR2(20); 4 v3_tx VARCHAR2(20); 5 begin 6 v2_tx:= rpad(lpad(v1_tx,10,'*'),15,'*'); 7 DBMS_OUTPUT.put_line(v2_tx); 8 v3_tx:= trim (both '*' from v2_tx); 9 DBMS_OUTPUT.put_line(v3_tx); 10 v3_tx:= trim (leading '*' from v2_tx); 11 DBMS_OUTPUT.put_line(v3_tx); 12 v3_tx:= trim (trailing '*' from v2_tx); 13 DBMS_OUTPUT.put_line(v3_tx); 14 end; 15 / ****Hello!***** Hello! Hello!***** ****Hello! PL/SQL procedure successfully completed. SQL>