MySQLクエリ：サブクエリが1行以上を返すと言うエラー - php、mysql、mysql-error-1242

2つのテーブルから複雑なクエリを実行しようとしています...これはスキルクイズからの質問です。

表

**Orders                                    Customer**s
id                                         id
date                                     first_name
shipping_amount                          last_name
order_status                             city
customer_id (Customers.id)             state

出力

-----------+------------+
| State     |  # Orders  |
+-----------+------------+
| NY        |  55        |
| CA        |  40        |
| NJ        |  33        |
| FL        |  21        |
| MO        |  12        |
+-----------+------------+

私は私の質問に取り組んできました、そしてそれはこのように見えます...

select DISTINCT state, (select count(id) Orders
from customers
group by state
ORDER BY Orders DESC) FROM Customers

副問合せが1行以上を返すというエラーが発生しました

回答：

これを試して：

SELECT c.state, COUNT(o.id) AS Orders
FROM Customers c, Orders o
WHERE o.customer_id = c.id
GROUP BY state
ORDER BY Orders DESC

サブクエリは必要ありません。

SELECT `Customers`.`state`, count(`Orders`.`id`)
as `orders FROM `Customers`
LEFT JOIN `Orders` ON `Customers`.`id` = `Orders`.`customer_id`
GROUP BY `Customers`.`state`
ORDER BY `orders` DESC

これを試して：

select DISTINCT state, (select count(id) as cnt, Orders from customers group by
state ORDER BY Orders DESC) Temp FROM Customers

SELECT c.state as State, COUNT(o.id) as NumOrders
FROM orders o
LEFT JOIN customers c ON (c.id = o.customer_id)
GROUP BY c.state