Hive综合应用案例-学生成绩查询

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 ----------

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
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 ----------

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 '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
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) t1,my_course course where t1.courseid=course.courseid) t2 group by t2.coursename;
---------- end ----------

第4关：数据库课程的平均成绩

---------- 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 '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
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') t1,my_score score where t1.courseid=score.courseid group by t1.courseid) t2,my_course t3 where t2.courseid=t3.courseid; 
---------- end ----------