题解 | 查询成绩

WITH
t1 AS (
SELECT
    sId
FROM SC
WHERE cId IN (1,2,3)
GROUP BY sId
HAVING (SUM(score) / 3) > 60)  -- 没有用AVG是因为，我认为缺考应该算作0分，比如（80+80+0）/3 而非AVG（80，80）

SELECT
    COUNT(*) AS 'count(*)'
FROM t1;