https://school.programmers.co.kr/learn/courses/30/lessons/298519
WITH WITH_RESULT AS (
SELECT *,
CASE
WHEN LENGTH IS NULL THEN 10
WHEN LENGTH <= 10 THEN 10
ELSE LENGTH
END AS 'ALT_LENGTH'
FROM FISH_INFO
)
SELECT COUNT(*) AS FISH_COUNT, MAX(LENGTH) AS MAX_LENGTH, FISH_TYPE
FROM WITH_RESULT
GROUP BY FISH_TYPE
HAVING AVG(ALT_LENGTH) >= 33
ORDER BY FISH_TYPE