Pig使用OR条件运算符抛出错误

Question

child = load 'file_name' using PigStorage('\t') as (child_code : chararray, child_id : int, child_precode_id : int);
parents = load 'file_name' using PigStorage('\t') as (child_id : int, child_internal_id : chararray, mother_id : int, father_id : int);
joined = JOIN child by child_id, parents by child_id;
mainparent = FOREACH joined GENERATE child_id as child_id_source, child_precode_id, child_code;
store parent into '(location of file)' using PigStorage('\t');
childfirst = JOIN  mainparent by (child_id_source), parents by (mother_id OR father_id);
firstgen = FOREACH childfirst GENERATE child_id, child_precode_id, child_code;   
store firstgen into 'file_location' using PigStorage('\t');

使用OR条件时出现以下错误：

  

错误org.apache.pig.PigServer - 解析期间的异常：错误   在解析期间。 Pig脚本无法解析：   NoViableAltException（91 @ []）无法解析：Pig脚本失败   解析：NoViableAltException（91 @ []）

Answer 1

以下语法不正确，Pig

中没有条件连接

childfirst = JOIN  mainparent by (child_id_source), parents by (mother_id OR father_id);

如果您想在两个键上加入一个键与另一个键的关系，那么创建两个连接并合并数据集。注意您可能必须区分结果关系。

childfirst = JOIN  mainparent by (child_id_source), parents by (mother_id);
childfirst1 = JOIN  mainparent by (child_id_source), parents by (father_id);
childfirst2 = UNION childfirst,childfirst1;
childfirst3 = DISTINCT childfirst2;
firstgen = FOREACH childfirst3 GENERATE child_id, child_precode_id, child_code;   
store firstgen into 'file_location' using PigStorage('\t');