how to do Transpose in corresponding few columns in pig/hive

Question

I was wondering is it possible to do transposition corresponding few columns in pig/hive.
as dealing with data i got below requirement

id      jan           


        

Answer 1

Yes this is definitely possible in Hive using the built-in "stack" UDF and a case statement. Something like this should work:

select id, value, CASE
WHEN value like 'j%'
THEN 'jan'
WHEN value like 'f%'
THEN 'feb'
WHEN value like 'm%'
THEN 'march'
ELSE ''
END as month
from table
lateral view stack(3, jan, feb, march) tb as value
;

Let me know if this works.

Answer 2

Pig doesn't have any built-in function to solve your requirement, but you can try the below approach, i guess it will work for you.

input.txt

1       j1      f1      m1
2       j2      f2      m2
3       j3      f3      m3

PigScript:

A = LOAD 'input.txt' USING PigStorage() AS (id,month1,month2,month3);
B = FOREACH A GENERATE FLATTEN(TOBAG(TOTUPLE(id,month1,'jan'),TOTUPLE(id,month2,'feb'),TOTUPLE(id,month3,'mar')));
DUMP B;

Output:

(1,j1,jan)
(1,f1,feb)
(1,m1,mar)
(2,j2,jan)
(2,f2,feb)
(2,m2,mar)
(3,j3,jan)
(3,f3,feb)
(3,m3,mar)