날짜를 char로 변환

# TO_CHAR => SELECT CAST(NOW() AS CHAR)

mysql은 CAST(expression AS data_type)또는 CONVERT(expression,type)로 형변환

oracle : SELECT TO_CHAR(SYSDATE,'RRRR-MM-DD') credate FROM DUAL
mysql : SELECT CAST(DATE_FORMAT(now(),'%Y-%m-%d') AS CHAR) credate;


# DECODE => CASE 예제..
SELECT CASE week WHEN 1 THEN '일요일' WHEN 2 THEN '월요일'
                  WHEN 3 THEN '화요일' WHEN 4 THEN '수요일'
                  WHEN 5 THEN '목요일' WHEN 6 THEN '금요일'
                  WHEN 7 THEN '토요일' END week
FROM STORM_COUNTER
WHERE year = 2002<!--"<-->