-- 5、查询所有同学的学生编号、学生姓名、选课总数、所有课程的总成绩

    科技2022-07-17  172

    SELECT st.s_id, st.s_name, COUNT(sc.c_id), CASE WHEN SUM(sc.s_score) IS NULL THEN 0.00 ELSE ROUND(SUM(sc.s_score),2) END AS '总成绩' FROM student st LEFT JOIN score sc ON sc.s_id=st.s_id GROUP BY st.s_id
    Processed: 0.009, SQL: 8