hive基本操作与应用

通过hadoop上的hive完成WordCount

启动hadoop

ssh localhost
cd /usr/local/hadoop
./sbin/start-dfs.sh
cd /usr/local/hive/lib
service mysql start
start-all.sh

Hdfs上创建文件夹

hdfs dfs -mkdir demo
hdfs dfs -ls /user/hadoop

上传文件至hdfs

hdfs dfs -put ./123.txt demo
hdfs dfs -ls /user/hadoop/demo

启动Hive

hive

创建原始文档表

create table docs(line string)

导入文件内容到表docs并查看

load data inpath '/user/hadoop/demo/123.txt' overwrite into table docs
select * from docs

用HQL进行词频统计，结果放在表word_count里

create table word_count as select word,count(1) as count from (select explode(split(line," ")) as word from docs) word group by word order by word;

查看统计结果

show tables;
select * from word_count;