SELECT txt FROM table ORDER BY DECODE(txt,'서울',1,'경기',2,'인천',3,4)
SELECT txt FROM table ORDER BY CASE txt WHEN '서울' THEN 1 WHEN '경기' THEN 2 WHEN '인천' THEN 3 ELSE 4 END
[출처] MYSQL DECODE CASE WHEN THEN|작성자 JSP 프로그래밍