如何使用Python脚本

来自官方文档

一、写 python 脚本：

import sys
import datetime

for line in sys.stdin:
  line = line.strip()
  userid, movieid, rating, unixtime = line.split('\t')
  weekday = datetime.datetime.fromtimestamp(float(unixtime)).isoweekday()
  print '\t'.join([userid, movieid, rating, str(weekday)])

二、添加脚本

add file /opt/datas/xxx.py

三、使用脚本

CREATE TABLE u_data_new (
  userid INT,
  movieid INT,
  rating INT,
  weekday INT)
ROW FORMAT DELIMITED
FIELDS TERMINATED BY '\t';

add FILE weekday_mapper.py;

INSERT OVERWRITE TABLE u_data_new
SELECT
  TRANSFORM (userid, movieid, rating, unixtime)		# 传入参数
  USING 'python weekday_mapper.py'					# 使用的脚本文件
  AS (userid, movieid, rating, weekday)				# 输出的字段
FROM u_data;

SELECT weekday, COUNT(*)
FROM u_data_new
GROUP BY weekday;