题解 | 分组过滤练习题
分组过滤练习题
https://www.nowcoder.com/practice/ddbcedcd9600403296038ee44a172f2d
SELECT
university,
AVG(question_cnt) AS avg_question_cnt,
AVG(answer_cnt) AS avg_answer_cnt
FROM user_profile
GROUP BY university
HAVING avg_question_cnt <5 OR avg_answer_cnt<20
此题不用WHERE的原因：
WHERE的判定早于GROUP BY
HAVING才是对分组后结果进行筛选的语法
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