Hi I'm making a function in Oracle but it gives me error and I don't know why

here is the function

```
CREATE OR REPLACE FUNCTION f_increment_salary15 (psueldo number)
return number 
IS
    v_ventas number;
    valorretornado number;
BEGIN 
    v_ventas:=0;
    valorretornado:=0;
    SELECT ee.nombre, COUNT(ve.IdEmpleado) INTO v_ventas FROM empleado ee INNER JOIN
    venta ve ON ee.idempleado = ve.idempleado 
    GROUP BY ee.nombre;
    IF v_ventas > 500 THEN
        valorretornado := psueldo + (psueldo * 0.15);
    ELSE valorretornado := psueldo + (psueldo * 0);
    END IF;
    return valorretornado;
END;
/

```

and here is the error

```
ERROR
--------- -------------------------------------------------------------
PL/SQL: SQL Statement ignored
PL/SQL: ORA-00947: not enough values

```