A WHILE loop is equivalent to a regular loop with an EXIT WHEN as the first statement.
The syntax is shown as follows.
while <<condition>>
loop
...<<set of statements>>...
end loop;
Nested WHILE Loop
SQL> SQL> declare-- from ww w .j a v a 2s.co m 2 v_ind_nr NUMBER; 3 v_current_nr NUMBER; 4 begin 5 v_current_nr:=0; -- should not be null! 6 while v_current_nr <= 25 7 loop 8 v_ind_nr:=0; -- reset each time 9 while v_ind_nr<4 10 loop 11 v_ind_nr:=v_ind_nr+1; 12 DBMS_OUTPUT.put_line(v_current_nr); 13 end loop; 14 v_current_nr:=v_current_nr+5; 15 end loop; 16 end; 17 / 0 0 0 0 5 5 5 5 10 10 10 10 15 15 15 15 20 20 20 20 25 25 25 25 PL/SQL procedure successfully completed. SQL>