大数据从入门到实战——Hive综合应用案例 ——学生成绩查询_头歌hive综合应用案例 — 学生成绩查询答案

第1关 计算每个班的语文总成绩和数学总成绩

---------- 禁止修改 ----------
 drop database if exists mydb cascade;
  set hive.auto.convert.join = false;
set hive.ignore.mapjoin.hint=false;
---------- 禁止修改 ----------


---------- begin ----------
---创建mydb数据库
create database if not exists mydb; 
---使用mydb数据库
use mydb;
---创建表score
create table if not exists score( name string comment '姓名',
chinese string comment '语文成绩', maths string comment '数学成绩' )
row format delimited fields terminated by ',' stored as textfile;
---导入数据：/root/data/step1_files/score.txt
load data local inpath '/root/data/step1_files/score.txt' into table score;
--创建表class
create table if not exists class( stuname string comment '姓名',
classname string comment '所在班级' )
row format delimited fields terminated by ',' stored as textfile;
---导入数据：/root/data/step1_files/class.txt
load data local inpath '/root/data/step1_files/class.txt' into table class;
---计算每个班的语文总成绩和数学总成绩，要求有哪科低于60分，该名学生成绩不计入计算。
select t1.classname,t1.chinese,t2.maths from(
select c.classname classname,sum(s.chinese) chinese from class c,score s
where c.stuname=s.name and s.chinese>=60 group by c.classname) t1,(
select c.classname classname,sum(s.maths) maths from class c,score s
where c.stuname=s.name and s.maths>=60 group by c.classname) t2
where t1.classname=t2.classname; 
--------- end ----------
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第2关 查询选修了3门以上的课程的学生姓名

---------- 禁止修改 ----------
 drop database if exists mydb cascade;
  set hive.auto.convert.join = false;
set hive.ignore.mapjoin.hint=false;
---------- 禁止修改 ----------


---------- begin ----------
---创建mydb数据库
create database if not exists mydb; 
---使用mydb数据库
use mydb;
---创建表my_stu
create table if not exists my_stu( id string comment '学生id',
name string comment '学生姓名', sex string comment '性别', age string comment '年龄', col string comment '所选的系' )
row format delimited fields terminated by ',' stored as textfile;
--导入数据：/root/data/step2_files/my_student.txt
load data local inpath '/root/data/step2_files/my_student.txt' into table my_stu;
--创建表my_score
create table if not exists my_score( id string comment '学生id',
courseid string comment '课程id', score string comment '成绩' )
row format delimited fields terminated by ',' stored as textfile;
---导入数据：/root/data/step2_files/my_score.txt
load data local inpath '/root/data/step2_files/my_score.txt' into table my_score; --创建表my_course
--创建表my_course
create table if not exists my_course( courseid string comment '课程id',
coursename string comment '课程名称' )
row format delimited fields terminated by ',' stored as textfile;
---导入数据：/root/data/step2_files/my_course.txt
load data local inpath '/root/data/step2_files/my_course.txt' into table my_course; 
---查询选修了3门以上的课程的学生姓名。
select stu.name,t.coursenum
from(
select id,count(courseid) coursenum from my_score
group by id) t,my_stu stu
where t.coursenum>=3 and stu.id=t.id; 
--------- end ----------
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第3关 课程选修人数

---------- 禁止修改 ----------
 drop database if exists mydb cascade;
  set hive.auto.convert.join = false;
set hive.ignore.mapjoin.hint=false;
---------- 禁止修改 ----------


---------- begin ----------
---创建mydb数据库
create database if not exists mydb;



---使用mydb数据库
use mydb;



---创建表my_stu
create table if not exists my_stu(
id string comment '学生id',
name string comment '姓名',
sex string comment '性别',
age string comment '年龄',
col string comment '所选的系')
row format delimited fields terminated by ','
stored as textfile;
---导入数据：/root/data/step2_files/my_student.txt
load data local inpath '/root/data/step2_files/my_student.txt' into table my_stu;



--创建表my_score
create table if not exists my_score(
id string comment '学生id',
courseid string comment '课程id',
score string comment '成绩')
row format delimited fields terminated by ','
stored as textfile;
---导入数据：/root/data/step2_files/my_score.txt
load data local inpath '/root/data/step2_files/my_score.txt' into table my_score;



--创建表my_course
create table if not exists my_course(
courseid string comment '课程id',
coursename string comment '课程名称')
row format delimited fields terminated by ','
stored as textfile;
---导入数据：/root/data/step2_files/my_course.txt
load data local inpath '/root/data/step2_files/my_course.txt' into table my_course;



---查询每个课程有多少人选修。
select t2.coursename, count(*)
from
    (
        select t1.name name, course.coursename coursename
        from
            (
                select stu.name name, score.courseid courseid
                from my_score score, my_stu stu
                where score.id = stu.id
            ) as t1,
            my_course course
        where t1.courseid = course.courseid
    )
    as t2
group by t2.coursename;
---------- end ---------- 
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第4关 shujuku课程的平均成绩

---------- 禁止修改 ----------
 drop database if exists mydb cascade;
  set hive.auto.convert.join = false;
set hive.ignore.mapjoin.hint=false;
---------- 禁止修改 ----------


---------- begin ----------
---创建mydb数据库
create database if not exists mydb;


---使用mydb数据库
use mydb;


---创建表my_stu
create table if not exists my_stu(
id string comment '学生id',
name string comment '姓名',
sex string comment '性别',
age string comment '年龄',
col string comment '所选的系')
row format delimited fields terminated by ','
stored as textfile;
---导入数据：/root/data/step2_files/my_student.txt
load data local inpath '/root/data/step2_files/my_student.txt' into table my_stu;


--创建表my_score
create table if not exists my_score(
id string comment '学生id',
courseid string comment '课程id',
score string comment '成绩')
row format delimited fields terminated by ','
stored as textfile;
---导入数据：/root/data/step2_files/my_score.txt
load data local inpath '/root/data/step2_files/my_score.txt' into table my_score;


--创建表my_course
create table if not exists my_course(
courseid string comment '课程id',
coursename string comment '课程名称')
row format delimited fields terminated by ','
stored as textfile;
---导入数据：/root/data/step2_files/my_course.txt
load data local inpath '/root/data/step2_files/my_course.txt' into table my_course;



---计算shujuku课程的平均成绩
select t3.coursename, t2.avg_score
from
    (
        select t1.courseid courseid, avg(score.score) avg_score
        from
            (
                select courseid
                from my_course
                where my_course.coursename = 'shujuku'
            ) as t1,
            my_score score
        where t1.courseid = score.courseid
        group by t1.courseid
    ) as t2,
    my_course t3
where t2.courseid = t3.courseid;

---------- end ----------
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