SQLD 기출문제 예상문제 178번

다음 문제를 풀어보세요.

다음 중 아래 SQL에 대한 설명으로 가장 적절한 것을 고르시오.

-- 고객 테이블
CREATE TABLE CUSTOMER (
    CUSTOMER_ID INT PRIMARY KEY,
    CUSTOMER_NAME VARCHAR(50),
    CITY VARCHAR(50)
);

-- 주문 테이블
CREATE TABLE ORDERS (
    ORDER_ID INT PRIMARY KEY,
    CUSTOMER_ID INT,
    ORDER_DATE DATE,
    TOTAL_AMOUNT DECIMAL(10, 2),
    FOREIGN KEY (CUSTOMER_ID) REFERENCES CUSTOMER(CUSTOMER_ID)
);

-- SQL 쿼리
SELECT C.CUSTOMER_NAME, COUNT(O.ORDER_ID) AS ORDER_COUNT
FROM CUSTOMER C
LEFT JOIN ORDERS O ON C.CUSTOMER_ID = O.CUSTOMER_ID
GROUP BY C.CUSTOMER_NAME
ORDER BY ORDER_COUNT DESC;