Pig拉丁求和计数查询

Question

我对Pig拉丁语很陌生，我正在尝试复制一个简单的SQL查询。示例输入数据表的形式如下：

**A   B  C**
  1   3  $5
  2   4  $6
  2   5  $7

我想数一数B栏中的行数和C行的总和，以便：

**A   Count(B)   Sum(C)**
  1   1          $5
  2   2          $13

或者在SQL中：

Select A, count(B), Sum(C)
From Data
Group by A

我怎样才能在猪身上做到这一点？

Answer 1

猪脚本:

input_data = LOAD 'input.csv' 
             USING PigStorage(',')
             AS (A:long, B:long, C:long);

input_data_grp_by_A = GROUP input_data BY A;

required_stats = FOREACH input_data_grp_by_A 
                 GENERATE group AS A,
                          COUNT(input_data.B) AS COUNT_B,
                          SUM(input_data.C) AS SUM_C;

输入:

1,3,5
2,4,6
2,5,7

输出: required_stats

(1,1,5)
(2,2,13)