hive 使用

参考资料

1. QuickStart  https://cwiki.apache.org/confluence/display/Hive/GettingStarted

2.Tutorial https://cwiki.apache.org/confluence/display/Hive/Tutorial

3.官方wiki https://cwiki.apache.org/confluence/display/Hive/Home

4.语法手册 https://cwiki.apache.org/confluence/display/Hive/LanguageManual

 

一.建表

CREATE EXTERNAL TABLE tablename(
  xx1 string, 
  xx2 string,
  xx3 int)
ROW FORMAT DELIMITED 
  FIELDS TERMINATED BY ',' 
STORED AS INPUTFORMAT 
  'org.apache.hadoop.mapred.TextInputFormat' 
OUTPUTFORMAT 
  'org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat'
LOCATION
  'hdfs://xx/tablename';

 

二.插入操作

insert overwrite table tablename

 

三.数据类型转换操作

select cast(xx AS int) from tablename;

 

四.group by 操作

insert overwrite table a select a1,a2,a3,count(*) from b group by a1,a2,a3;

执行group by操作需要select那个字段group by就要有哪个字段

 

五.字符串split操作

select split(a1,",") from a;

split 操作生成一个列表