(SELECT COUNT(motorbike.`owner_id`) as count,owner.`name`,transport.`type` FROM transport,owner,motorbike WHERE transport.type='motobike'
AND owner.`owner_id`=motorbike.`owner_id`
AND transport.`type_id`=motorbike.`motorbike_id` GROUP BY motorbike.owner_id)
UNION ALL
(SELECT COUNT(car.`owner_id`) as count,owner.`name`,transport.`type` FROM transport,owner,car WHERE transport.type='car'
AND owner.`owner_id`=car.`owner_id`
AND transport.`type_id`=car.`car_id` GROUP BY car.`owner_id`)
上記のクエリは、以下のような結果を返します。
count name
1 Linda
2 Mary
1 Steve
1 Linda
このクエリは、所有者が所有しているトランスポートの数をカウントします。 Lindaには1台の車と1台のバイクがあるため、結果は次のようになります。
count name
2 Linda
2 Mary
1 Steve
私はこのクエリを試しましたが、エラーを返します:
(SELECT COUNT(motorbike.`owner_id`),owner.`name`,transport.`type` FROM transport,owner,motorbike WHERE transport.type='motobike'
AND owner.`owner_id`=motorbike.`owner_id`
AND transport.`type_id`=motorbike.`motorbike_id`)
UNION ALL
(SELECT COUNT(car.`owner_id`),owner.`name`,transport.`type` FROM transport,owner,car WHERE transport.type='car'
AND owner.`owner_id`=car.`owner_id`
AND transport.`type_id`=car.`car_id`) GROUP BY motorbike.owner_id
誰でも私を助けてくれますか?
select sum(qty), name
from (
select count(m.owner_id) as qty, o.name
from transport t,owner o,motorbike m
where t.type='motobike' and o.owner_id=m.owner_id
and t.type_id=m.motorbike_id
group by m.owner_id
union all
select count(c.owner_id) as qty, o.name,
from transport t,owner o,car c
where t.type='car' and o.owner_id=c.owner_id and t.type_id=c.car_id
group by c.owner_id
) t
group by name
これはあなたの後にあるかもしれません:
SELECT Count(Owner_ID), Name
FROM (
SELECT M.Owner_ID, O.Name, T.Type
FROM Transport As T, Owner As O, Motorbike As M
WHERE T.Type = 'Motorbike'
AND O.Owner_ID = M.Owner_ID
AND T.Type_ID = M.Motorbike_ID
UNION ALL
SELECT C.Owner_ID, O.Name, T.Type
FROM Transport As T, Owner As O, Car As C
WHERE T.Type = 'Car'
AND O.Owner_ID = C.Owner_ID
AND T.Type_ID = C.Car_ID
)
GROUP BY Owner_ID
これを編集してみてください:
(SELECT COUNT(motorbike.owner_id),owner.name,transport.type FROM transport,owner,motorbike WHERE transport.type='motobike' AND owner.owner_id=motorbike.owner_id AND transport.type_id=motorbike.motorbike_id GROUP BY motorbike.owner_id)
UNION ALL
(SELECT COUNT(car.owner_id),owner.name,transport.type FROM transport,owner,car WHERE transport.type='car' AND owner.owner_id=car.owner_id AND transport.type_id=car.car_id GROUP BY car.owner_id)