풀이 코드
SELECT COUNT(USER_ID) AS USERS
FROM USER_INFO
WHERE DATE_FORMAT(JOINED, "%Y") = "2021"
AND AGE >= 20 AND AGE <= 29
항상 성장하는 개발자 최동혁입니다.
SELECT COUNT(USER_ID) AS USERS
FROM USER_INFO
WHERE DATE_FORMAT(JOINED, "%Y") = "2021"
AND AGE >= 20 AND AGE <= 29