Question

查询每位同学的课程门数、总成绩、平均成绩”的SQL语句是什么？

Answer 1

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) 

删除：delete from table1 where 范围 

更新：update table1 set field1=value1 where 范围 

查找：select * from table1 where field1 like ’%value1%’ 

排序：select * from table1 order by field1,field2 [desc] 

总数：select count as totalcount from table1 

求和：select sum(field1) as sumvalue from table1 

平均：select avg(field1) as avgvalue from table1 

最大：select max(field1) as maxvalue from table1 

最小：select min(field1) as minvalue from table1