day06

SELECT
    student.SId,
    student.Sname,
    AVG( sc.score ) 
FROM
    sc,
    student 
WHERE
    sc.score < 60 AND sc.SId = student.SId GROUP BY sc.SId HAVING COUNT( score ) >= 2

SELECT
    student.* 
FROM
    student,
    sc 
WHERE
    student.SId = sc.SId 
    AND sc.CId = 01 
    AND sc.score < 60 
ORDER BY
    sc.score