SQL语句如下： SELECT 学号, Count(课程编号) AS 课程总数, Sum(成绩) AS 总分数, Avg(成绩) AS 平均分 FROM 成绩表 GROUP BY 学号; SQL常用操作语句如下： 选择：select * from table1 where 范围 插入：insert into table1(field1,field2) values(value1,value2)