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
【注】
聚合函数结果作为筛选条件时,不能用 where
,而是用 having
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
【注】
聚合函数结果作为筛选条件时,不能用 where
,而是用 having