Aggregation functions in PIG

Aggregation functions in PIG

  4:12 PM    ssaikgame

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Example1:

year	price
2015	60
2014	45
2016	34
2014	75
2015	45
2014	41

I would like to get the result as, total price of the item by year.

grunt> file = load '/tmp/yearprice.txt' using PigStorage(',') as (year:int,price:float);

grunt> data = foreach file generate year, price by $0 > 1;

grunt> group = group data by year;

grunt> sum = foreach group generate group as year, SUM(data.price);

grunt> dump sum;

2014 161
2015 105
2016 34


Example 2:

id1, 1,on,400 

id1, 2,off,100

id2, 3,on,200

i would like to get the result as "sum of $3 if $2 is 0, by ID $0"

grunt> file = load '/tmp/file' using PigStorage(',');

grunt> refineData = foreach file generate $0, $1, (($2 == 'on') ? $3 : 0);

grunt> grp = group refineData by $0;

grunt> sum = foreach grp generate group as id, SUM(refineData.$2);

grunt> dump sum;

id1, 500
id2, 200