SELECT 专业 AS SUBS(学号,3,2),平均分 AS AVG(成绩) FROM 选课 WHERE 课程号="101" GROUP BY 专业 SELECT SUBS(学号,3,2) AS 专业,AVG(成绩) AS 平均分 FRON 选课 WHERE 课程号="101" GROUP BY 1 SELECT SUBS(学号,3,2) AS 专业,AVG(成绩) AS 平均分 FRON 选课 WHERE 课程号="101" ORDER BY 专业 SELECT 专业 AS SUBS(学号,3,2),平均分 AS AVG(成绩) FRON 选课 WHERE 课程号="101" ORDER BY 1