如何对猪脚本中的多列进行分组

Question

以下 SQL 查询的 pig 等效脚本应该是什么：

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

对于表 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

输出：

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

Answer 1

Ref : https://pig.apache.org/docs/r0.11.1/basic.html#GROUP, you can find a multi-group example

对于您的用例，下面的代码应该足够了

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;

如何对猪脚本中的多列进行分组

How to Group By on multiple column in a pig script

apache-pig