hadoop - pig 错误 : while reading the Attribute from a Relation

Question

嗨，我正在使用下面的代码来执行订单操作，但它抛出了 Invalid field projection where As The Relation Has the column 的错误。

grunt> byts = ORDER B BY JB_DLT::job_id DESC;

错误

2016-09-20 07:32:56,815 [main] ERROR org.apache.pig.tools.grunt.Grunt - ERROR 1025: Invalid field projection. Projected field [JB_DLT::job_id] does not exist in schema: group:tuple(JB_ASGNMNT::JB_DLT::job_id:bigdecimal,JOB_ASNMNT_STS_DLT::job_assignment_status_cd:chararray),a:bag{:tuple(JB_ASGNMNT::JB_DLT::job_id:bigdecimal,JOB_ASNMNT_STS_DLT::job_assignment_status_cd:chararray,JOB_ASNMNT_STS_DLT::job_assignment_status_id:bigdecimal,JOB_ASNMNT_STS_DLT::actual_status_dt:datetime)}.

grunt> 描述 B;

B: {group: (JB_ASGNMNT::JB_DLT::job_id: bigdecimal,JOB_ASNMNT_STS_DLT::job_assignment_status_cd: chararray),a: {(JB_ASGNMNT::JB_DLT::job_id: bigdecimal,JOB_ASNMNT_STS_DLT::job_assignment_status_cd: chararray,JOB_ASNMNT_STS_DLT::job_assignment_status_id: bigdecimal,JOB_ASNMNT_STS_DLT::actual_status_dt: datetime)}}

如何在 ORDER BY 子句中读取该列数据。请分享您的想法..

Answer 1

虽然 JB_DLT::job_id 存在但是 Pig latin 找不到(有 JB_ASGNMNT::JB_DLT::job_id)，编辑语句 B 添加 JB_DLT::job_id 作为 job_id 。然后运行:

grunt> byts = ORDER B BY job_id DESC;

或者

byts = ORDER B BY JB_ASGNMNT::JB_DLT::job_id DESC;