如何從一袋元組中提取截然不同的東西？

Question

所以我有豬下面的數據結構描述後：

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| summed_hours_and_miles_by_driver  | group:int  | :bag{:tuple(driver_name:chararray)}    | total_hours:long  | total_miles:long  | 
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|          | 27   | {(Mark Lochbihler), ..., (Mark Lochbihler)}  | 220     | 11006    | 
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的想法是，驅動程序名稱（馬克Lochbihler）的元組的包被複制多次。 我怎樣才能限制它在一個單一的名字那裏有像SQL中的DISTINCT？

Answer 1

使用Distinct，假設A是你的關係是這樣的

summed_hours_and_miles_by_driver = FOREACH grp GENERATE 
             group, 
             org.apache.pig.builtin.Distinct(A.driver_name), 
             total_hours, 
             total_miles;