【Hive学习之四】Hive 案例

环境
　　虚拟机：VMware 10
　　Linux版本：CentOS-6.5-x86_64
　　客户端：Xshell4
　　FTP：Xftp4
　　jdk8
　　hadoop-3.1.1
　　apache-hive-3.1.1

一、需求：统计出掉线率最高的前10基站
　　数据：
　　　　record_time：通话时间
　　　　imei：基站编号
　　　　cell：手机编号
　　　　drop_num：掉话的秒数
　　　　duration：通话持续总秒数

1、建表

--数据表
create table cell_monitor(
record_time string,
imei string,
cell string,
ph_num string,
call_num string,
drop_num int,
duration int,
drop_rate DOUBLE,
net_type string,
erl string
)
ROW FORMAT DELIMITED FIELDS TERMINATED BY ','
STORED AS TEXTFILE;

--结果表
create table cell_drop_monitor(
imei string,
total_call_num int,
total_drop_num int,
d_rate DOUBLE
)
ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t'
STORED AS TEXTFILE;

2、导入数据

LOAD DATA LOCAL INPATH '/root/cdr_summ_imei_cell_info.csv' OVERWRITE INTO TABLE cell_monitor;

#展示前10条
hive> select * from cell_monitor limit 10;
OK
record_time    imei    cell    ph_num    call_num    NULL    NULL    NULL    net_type    erl
-- ::+        -                    0.0    G
-- ::+        -                    0.0    G
-- ::+        -                    0.0    G
-- ::+        -                    0.0    G
-- ::+        -                    0.0    G
-- ::+        -                    0.0    G
-- ::+        -                    0.0    G
-- ::+        -                    0.0    G
-- ::+        -                    0.0    G
Time taken: 0.132 seconds, Fetched:  row(s)
hive> 

出现NULL 是因为字段类型是非字符串类型，匹配不上 所以显示NULL

3、查询掉线率 倒序排列

from cell_monitor cm
insert overwrite table cell_drop_monitor
select cm.imei,sum(cm.drop_num),sum(cm.duration),sum(cm.drop_num)/sum(cm.duration) d_rate
group by cm.imei
sort by d_rate desc;

二、使用hive实现wordcount

1、建表

--数据表
create table docs(line string);
--结果表
create table wc(word string, totalword int);

hive> create table docs(line string);
OK
Time taken: 0.722 seconds
hive> create table wc(word string, totalword int);
OK
Time taken: 0.045 seconds

2、导入数据

/root/wc:

hadoop hello world
hello hadoop
hbase zookeeper
name name name

导入数据：

hive> load data local inpath '/root/wc' into table docs;
Loading data to table default.docs
OK
Time taken: 0.392 seconds
hive> select * from docs;
OK
hadoop hello world
hello hadoop
hbase zookeeper
name name name
Time taken: 1.728 seconds, Fetched: 4 row(s)

3、统计

hive> select explode(split(line, ' ')) as word from docs;
OK
hadoop
hello
world
hello
hadoop
hbase
zookeeper
name
name
name
Time taken: 0.377 seconds, Fetched:  row(s)
hive> 

下面统计语句会产生MR任务：

from (select explode(split(line, ' ')) as word from docs) w
insert into table wc
select word, count() as totalword
group by word
order by word;

4、查询结果

hive> select * from wc;
OK
hadoop 2
hbase 1
hello 2
name 3
world 1
zookeeper 1
Time taken: 0.121 seconds, Fetched: 6 row(s)
hive>