答案是,UTF-8不是按照字母顺序,汉字GBK是按照字母顺序。
[1]select sum(成绩)
from score
where 课程号='0002'
[2]select count(distinct 学号) as 学生人数
from score
[1]select 课程号,max(成绩) as 最高分,min(成绩) as 最低分
from score
group by 课程号
[2]select 课程号,count(学号)
from score
group by 课程号
[3]select 性别,count(*)
from student
group by 性别
[1]select 学号,average(成绩)
from score
group by 学号
having avg(成绩)>60;
[2]select 学号,count(课程号) as 选修课程数目
from score
group by 学号
having count(课程号) >=2;
[3]select 姓名,count(*) as 人数
from student
group by 姓名
having count(*)>=2;
select 课程号,avg(成绩)
from socre
group by 课程号
having avg(成绩)>=80;
[1]select 课程号
from score
where 成绩<60
order by 课程号 desc;
[2]
select 课程号,avg(成绩) as 平均成绩
from score
group by 课程号
order by 平均成绩 asc,课程号 desc;
select 学号
from score
where 课程编号=‘04’ and 成绩<60
order by 分数 desc;
select 课程号,count(学号) as '学生选修人数'
from score
group by 课程号
having count(学号)>2
order by 学生选修人数 desc,课程号 asc;
select 学号,avg(成绩)
from score
where 成绩<60
group by 学号
having count(学号)>2
考察 not in
注意升序其实可以忽略不写asc也没关系
这道题值得一说,题目要求查找1984年获奖者和主题按主题和获胜者名称排序,并把化学奖和物理奖排到最后显示。
这道题排序的思路是,用in('Physics','Chemistry')来如果不在里面的话返回0,在里面的话返回1,然后默认升序0-1,所以如果属于物理和化学返回1,自然就到后面去了。
好了鸭哥祝大家前程似锦,886