Cómo encontrar LEFT OUTER JOIN o RIGHT OUTER JOIN con ORACLE JOIN (+)

Aclare cómo encontrar la combinación externa derecha e izquierda correctamente con un ejemplo

Intentaré mostrar la diferencia entre la sintaxis de unión externa de Oracle y la sintaxis ANSI/ISO .

UNIÓN EXTERNA IZQUIERDA -

SELECT e.last_name,
  d.department_name
FROM employees e,
  departments d
WHERE e.department_id = d.department_id(+);

SELECT e.last_name,
  d.department_name
FROM employees e
LEFT OUTER JOIN departments d
ON (e.department_id = d.department_id);

UNIÓN EXTERNA DERECHA -

SELECT e.last_name,
  d.department_name
FROM employees e,
  departments d
WHERE e.department_id(+) = d.department_id;

SELECT e.last_name,
  d.department_name
FROM employees e
RIGHT OUTER JOIN departments d
ON (e.department_id = d.department_id);

UNIÓN EXTERNA COMPLETA -

Antes del soporte nativo de hash full externaljoin en 11gR1, Oracle convertía internamente FULL OUTER JOIN de la siguiente manera:

SELECT e.last_name,
  d.department_name
FROM employees e,
  departments d
WHERE e.department_id = d.department_id(+)
UNION ALL
SELECT NULL,
  d.department_name
FROM departments d
WHERE NOT EXISTS
  (SELECT 1 FROM employees e WHERE e.department_id = d.department_id
  );

SELECT e.last_name,
  d.department_name
FROM employees e
FULL OUTER JOIN departments d
ON (e.department_id = d.department_id);

Echa un vistazo a esto.