PIG 中的 CASE 语句 [英] CASE statement in PIG

问题描述

我正在尝试根据几个条件从地理编码"中提取顶点代码":

I am trying to extract 'vertex_code' from 'geocode' based on few conditions:

SUBSTRING(geocode,0,2) ----> Code
00-51 ----> 01
70    ----> 03
61-78 ----> 04
Else ----> 00

现在必须将获得的code"值与geocode"值(前缀)连接，并再次与末尾的 00(后缀)连接以形成vertex_code"

Now the obtained 'code' value has to be concatenated with 'geocode' value (prefix) and again concatenated with 00 at the end (suffix) to form the 'vertex_code'

例如:geocode = 44556677

如果 SUBSTRING(geocode,0,2) 在 00-51 之间，则 code=01

if SUBSTRING(geocode,0,2) is between 00-51, then code=01

因此顶点代码 = 014455667700

hence vertex_code = 014455667700

下面是我的脚本:

item = load '/user/item.txt' USING PigStorage('|') AS (load_id:chararray, record_type:chararray, geocode:chararray);

newitem = FOREACH item GENERATE load_id, record_type,
(CASE (SUBSTRING(geocode,0,2))
 WHEN 00-51 THEN 'CONCAT(01,CONCAT(geocode,00))'
 WHEN 70 THEN 'CONCAT(03,CONCAT(geocode,00))'
 WHEN 61-78 THEN 'CONCAT(04,CONCAT(geocode,00))'
 ELSE 'CONCAT(00,CONCAT(geocode,00))'
 END) AS vertex_code;

DUMP newitem;

我收到以下错误:

2018-01-29 09:00:40,645 [main] 错误 org.apache.pig.tools.grunt.Grunt -ERROR 1039: (Name: Equal Type: null Uid: null) Equal 中的类型不兼容运算符左侧:chararray 右侧:int

2018-01-29 09:00:40,645 [main] ERROR org.apache.pig.tools.grunt.Grunt - ERROR 1039: (Name: Equal Type: null Uid: null)incompatible types in Equal Operator left hand side:chararray right hand side:int

非常感谢您的帮助.

推荐答案

你必须把它转换成 int 然后比较

You have to cast it to int and then compare

newitem = FOREACH item GENERATE load_id, record_type,
(CASE 
 WHEN ((int)SUBSTRING(geocode,0,2) <= 51  THEN CONCAT('01',CONCAT(geocode,'00'))
 WHEN ((int)SUBSTRING(geocode,0,2) = 70 THEN CONCAT('03',CONCAT(geocode,'00'))
 WHEN ((int)SUBSTRING(geocode,0,2) >= 61 and ((int)SUBSTRING(geocode,0,2) <=78 THEN CONCAT('04',CONCAT(geocode,'00'))
 ELSE CONCAT('00',CONCAT(geocode,'00'))
 END) AS vertex_code;

DUMP newitem;

这篇关于PIG 中的 CASE 语句的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！