Дана таблица:
ID | FAMILY | ANIMAL | COLOR |
---|---|---|---|
1 | mammal | dog | brown |
2 | mammal | zebra | black,white |
3 | fish | shark | gray |
4 | bird | gull | white |
5 | bird | pelican | white |
6 | fish | trout | gray |
SELECT a1.animal, a2.animal, a1.color FROM animals a1, animals a2 WHERE a1.color = a2.color AND a1.animal <> a2.animal;Выборки, эквивалентные результату запроса, возвращают команды:
(Отметьте один правильный вариант ответа.)
Варианты ответа
SELECT a1.animal, a2.animal, a1.color FROM animals a1 NATURAL INNER JOIN animals a2 WHERE a1.animal <> a2.animal;
SELECT a1.animal, a2.animal, a1.color FROM animals a1 INNER JOIN animals a2 ON a1.color = a2.colorWHERE a1.animal <> a2.animal;(Верный ответ)
SELECT a1.animal, a2.animal, a1.color FROM animals a1 CROSS JOIN animals a2 WHERE a1.animal <> a2.animal;
SELECT a1.animal, a2.animal, a1.color FROM animals a1 FULL JOIN animals a2 USING (color)WHERE a1.animal <> a2.animal;