AUTHOR_ID를 기준으로 BOOK과 AUTHOR 테이블이 연결되기 때문에 JOIN ON 변수=변수 로 작성해준다
그리고 결과 예시의 DATE 형식이 기존에 주어진 PUBLISHED_DATE의 형식과 다르기 때문에 이를 바꿔줘야 한다
DATE_FORMAT(날짜, 형식) 함수와 날짜 출력 기호를 활용하여 SQL 구문을 작성해준다
SELECT BOOK_ID, AUTHOR_NAME, DATE_FORMAT(PUBLISHED_DATE, '%Y-%m-%d') AS PUBLISHED_DATE
FROM BOOK AS B
JOIN AUTHOR AS A ON A.AUTHOR_ID = B.AUTHOR_ID
WHERE CATEGORY='경제'
ORDER BY PUBLISHED_DATE+) SQL 날짜 출력 기호
%a Abbreviated weekday name (Sun to Sat)
%b Abbreviated month name (Jan to Dec)
%c Numeric month name (0 to 12)
%D Day of the month as a numeric value, followed by suffix (1st, 2nd, 3rd, ...)
%d Day of the month as a numeric value (01 to 31)
%e Day of the month as a numeric value (0 to 31)
%f Microseconds (000000 to 999999)
%H Hour (00 to 23)
%h Hour (00 to 12)
%I Hour (00 to 12)
%i Minutes (00 to 59)
%j Day of the year (001 to 366)
%k Hour (0 to 23)
%l Hour (1 to 12)
%M Month name in full (January to December)
%m Month name as a numeric value (00 to 12)
%p AM or PM
%r Time in 12 hour AM or PM format (hh:mm:ss AM/PM)
%S Seconds (00 to 59)
%s Seconds (00 to 59)
%T Time in 24 hour format (hh:mm:ss)
%U Week where Sunday is the first day of the week (00 to 53)
%u Week where Monday is the first day of the week (00 to 53)
%V Week where Sunday is the first day of the week (01 to 53). Used with %X
%v Week where Monday is the first day of the week (01 to 53). Used with %x
%W Weekday name in full (Sunday to Saturday)
%w Day of the week where Sunday=0 and Saturday=6
%X Year for the week where Sunday is the first day of the week. Used with %V
%x Year for the week where Monday is the first day of the week. Used with %v
%Y Year as a numeric, 4-digit value
%y Year as a numeric, 2-digit value
출처 : https://www.w3schools.com/mysql/func_mysql_date_format.asp
