SELECT
st.s_id,
st.s_name,
CASE WHEN AVG(sc.s_score) IS NULL THEN '无' ELSE ROUND (AVG(sc.s_score) ,2) END AS '平均分'
FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id
GROUP BY st.s_id
HAVING AVG(sc.s_score)<60 OR AVG(sc.s_score) IS NULL
Processed:
0.013, SQL:
8
