While Loop Error

Hi,

You need to initialize suma, like you initialize.x:

DECLARE
    x    NUMBER (10) := 1;
    z    NUMBER;
    suma NUMBER      := 0;
BEGIN
    WHILE x <= 3
    LOOP
        z := (x * 2) + 4;
        suma := suma + z;
        x := x + 1;
    END LOOP;

    DBMS_OUTPUT.PUT_LINE (suma || ' = final suma');
END;
/

NULL plus anything is NULL, so if suma is NULL when you reach this statement

suma := suma + z;

then it will be NULL after executing that statement.

Also, you're going through the loop an extra time.  Since x starts at 0, yu're starting the loop when x is 0, 1, 2 and 3, and incrementing the sum for x as 1, 2, 3 and 4.

(I see Galo caught the same thing while I was revising this message.)

Hi,

You can do this in pure SQL, too:

SELECT  SUM ((2 * LEVEL) + 4)  AS suma
FROM    dual
CONNECT BY  LEVEL  <= 3
;