MySQL 쿼리 : 하위 쿼리가 두 행 이상을 반환하는 오류

Question

두 테이블에서 복잡한 쿼리를 수행하려고합니다. 스킬 퀴즈에서 질문입니다.

테이블

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

출력 그것은 나에게 하위 쿼리라는 오류를 준

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

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

내 쿼리에 노력하고있다 그것은 다음과 같습니다 ... 1 행 이상을 반환합니다.

Answer 1

시험해보기 :

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 

하위 쿼리가 필요하지 않습니다.

Answer 2

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 

Answer 3

이 시도 :

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

Answer 4

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