how to increment an integer

HI ALL
i am a newbie in SQL.tell me how to increment an integer variable, i dont want autoincrement.Where is this integer? In a table in a variable, ...?
In a table: UPDATE MYTAB SET INT1=INT1+1 WHERE <some condition>;
In a variable: v_int:=v_int+1;
In a loop: FOR i1 IN 1..n LOOP...
In a query: SELECT INT1 + 1 INTO v_int from MYTAB...;

:confused:sql