如何組通過對多列在豬腳本

Question

應該是什麼下面的SQL查詢的豬等同腳本：

SELECT fld1, fld2, fld3, SUM(fld4) 
FROM Table1 
GROUP BY fld1, fld2, fld3; 

對於表1：

A B C 2 X Y Z 
A B C 3 X Y Z 
A B D 2 X Y Z 
A C D 2 X Y Z 
A C D 2 X Y Z 
A C D 2 X Y Z 

OUTPUT：

A B C 5   
A B D 2   
A C D 6   

Answer 1

參考：https://pig.apache.org/docs/r0.11.1/basic.html#GROUP，你可以 找到多組例如

爲了您的用例，下面的代碼應該足夠

A = load 'input.csv' using PigStorage(',') AS (fld1:chararray,fld2:chararray,fld3:chararray,fld4:long,fld5:chararray,fld6:chararray,fld7:chararray); 
B = FOREACH(GROUP A BY (fld1,fld2,fld3)) GENERATE FLATTEN(group) AS (fld1,fld2,fld3), SUM(A.fld4) AS fld4_aggr; 
DUMP B;