这是@bluefeet的建议的替代方法，该建议有些相似，但避免了联接（相反，将较高级别的分组应用于已分组的结果集）：
SELECt year, MAX(CASE animal WHEN 'kittens' THEN avg_price END) AS "kittens", MAX(CASE animal WHEN 'puppies' THEN avg_price END) AS "puppies"FROM ( SELECt animal, year, COUNT(*) AS cnt, AVG(Price) AS avg_price FROM tab_test GROUP BY animal, year) sWHERe cnt >= 3GROUP BY year;
