hive udf使用

0.要继承org.apache.hadoop.hive.ql.exec.UDF类实现evaluate

自定义函数调用过程：

1.添加jar包（在hive命令行里面执行）

hive> add jar /root/NUDF.jar;

2.创建临时函数

hive> create temporary function getNation as 'cn.itcast.hive.udf.NationUDF';

3.调用

hive> select id, name, getNation(nation) from beauty;

4.将查询结果保存到HDFS中

hive> create table result row format delimited fields terminated by '\t' as select * from beauty order by id desc;

hive> select id, getAreaName(id) as name from tel_rec;

create table result row format delimited fields terminated by '\t' as select id, getNation(nation) from beauties;