猪条件算子

Question

考虑以下关系

test = LOAD 'input' USING PigStorage(',') as (a:chararray, b:chararray);

有没有办法实现以下

if (b == 1) {
    a = 'abc';
else if (b == 2) {
    a = 'xyz';
else 
    // retain whatever is there in the column 'a'

Answer 1

您可以执行FOREACH并使用三元运算符，如下所示。

test2 = FOREACH test GENERATE (b=='1' ? 'abc' : (b=='2' ? 'xyz' : a)) AS a, b;