SQLD CBT 기출문제 예상문제 891번

다음 문제를 풀어보세요.

다음 중 아래 계좌 거래 테이블에 대해 각 계좌(ACCOUNT_ID)별로 거래일시(TX_DATE) 순서에 따른 누적 잔액(RUNNING_BALANCE)을 계산하고자 할 때, 성능과 표준 SQL 문법을 고려하여 가장 적절하게 작성된 SQL을 고르시오.

[테이블 구조]

ACCOUNT_TX (계좌 거래 테이블)

ACCOUNT_ID (계좌 ID)
TX_DATE (거래일시)
AMOUNT (거래금액 - 입금은 양수, 출금은 음수)

SELECT ACCOUNT_ID, TX_DATE, AMOUNT, 
       SUM(AMOUNT) OVER (PARTITION BY ACCOUNT_ID ORDER BY TX_DATE ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS RUNNING_BALANCE 
FROM ACCOUNT_TX;

SELECT ACCOUNT_ID, TX_DATE, AMOUNT, 
       SUM(AMOUNT) OVER (ORDER BY TX_DATE) AS RUNNING_BALANCE 
FROM ACCOUNT_TX;

SELECT ACCOUNT_ID, TX_DATE, AMOUNT, 
       SUM(AMOUNT) OVER (PARTITION BY ACCOUNT_ID ORDER BY TX_DATE ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING) AS RUNNING_BALANCE 
FROM ACCOUNT_TX;

SELECT ACCOUNT_ID, TX_DATE, AMOUNT, 
       CUM_SUM(AMOUNT) OVER (PARTITION BY ACCOUNT_ID ORDER BY TX_DATE) AS RUNNING_BALANCE 
FROM ACCOUNT_TX;