十一章 连接,分组查询 上机练习一

--上机练习一--NO.1SELECT SUM(ClassHour) AS 总学时数 FROM  Subject GROUP BY Gradeid ORDER BY SUM(ClassHour) --NO.2SELECT AVG(StudentResult) AS 平均分 FROM Result GROUP BY StudentNo ORDER BY AVG(StudentResult)--NO.3SELECT AVG(StudentResult) AS 平均分 FROM Result GROUP BY SubjectId ORDER BY AVG(StudentResult)--NO.4SELECT SUM(StudentResult) AS 总分 FROM Result GROUP BY StudentNo ORDER BY SUM(StudentResult) DESC