SELECT CASE WHEN age BETWEEN 0 AND 9 THEN '1.10대이하'
            WHEN age BETWEEN 10 AND 19 THEN '2.10대'
            WHEN age BETWEEN 20 AND 29 THEN '3.20대'
            WHEN age BETWEEN 30 AND 39 THEN '4.30대'
            WHEN age BETWEEN 40 AND 49 THEN '5.40대'
            WHEN age BETWEEN 50 AND 59 THEN '6.50대'
            WHEN age BETWEEN 60 AND 69 THEN '7.60대'
            WHEN age IS NULL           THEN '9.알수없음'
            ELSE '8.70대 이상'
       END ages, survived, COUNT(*) cnt
  FROM titanic
 GROUP BY 1, 2
 ORDER BY 1, 2;