PIG 中的 CASE 语句

Question

我正在尝试根据以下几个条件从 'geocode' 中提取 'vertex_code'：

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）连接起来，并再次与末尾的 00（后缀）连接以形成 'vertex_code'

例如：geocode = 44556677

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

因此 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] 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

非常感谢帮助。

Answer 1

你必须将它转换为 int 然后比较

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;

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