CODEWITHSUNDEEP
arraysdictionaryhivehiveqltranspose
linux developer
linux developer

Reputation: 831

hive - Is it possible to create columns from Map

I am seeking some advise on understanding the possibility of converting Map in hive to columns (transpose) Some sample records as and how i like to represent them are given below.

{"AR":["Fasdfadsfasd","Hasdfasdf"]}
{"DR":["Aasdfads","Baasdfasdf","Iasdfadsf","Zasdfasdf"]}
{"PR":["Easdfadsf","Gasdfadsfads"]}
{"SR":["Casdfasdf","Dasdfadsf","Jasdfasdfa"]}


AR              DR              PR             SR
Fasdfadsfasd    Aasdfads        Easdfadsf      Casdfasdf
Hasdfasdf       Baasdfasdf      Gasdfadsfads   Dasdfadsf
NULL            Iasdfadsf       NULL           Jasdfasdfa
NULL            Zasdfasdf       NULL           NULL

Appreciate the help!

Upvotes: 1

Views: 84

Answers (1)

leftjoin
leftjoin

Reputation: 38325

See comments in the code. Transformation steps were not combined intentionally to make it easier to understand:

with your_table as ( --use your_table instead of this 
select stack(4,
             '{"AR":["Fasdfadsfasd","Hasdfasdf"]}',
             '{"DR":["Aasdfads","Baasdfasdf","Iasdfadsf","Zasdfasdf"]}',
             '{"PR":["Easdfadsf","Gasdfadsfads"]}',
             '{"SR":["Casdfasdf","Dasdfadsf","Jasdfasdfa"]}'
             ) as src
)

select max(AR) AR, max(DR) DR, max(PR) PR, max(SR) SR --group by position
from
(
select case when key='AR' then value end AR, --transpose
       case when key='DR' then value end DR,
       case when key='PR' then value end PR,
       case when key='SR' then value end SR,
       pos
from
(
select s.key, regexp_replace(v.value,'(^\\")|(\\"$)','') value, v.pos --remove quotes from value
from
(
select regexp_replace(m[0],'(^\\")|(\\"$)','') key, regexp_replace(m[1],'\\[|\\]','') value --remove [] from value and unquote key
from
(
select split(
       regexp_replace(src,'\\{|\\}',''), --remove curly braces
       '[:]') as m --split map key and value
  from your_table t
)s
)s lateral view outer posexplode(split(value,'\\",\\"')) v as pos, value
)s
)s 
group by pos;

Result:

ar           dr           pr           sr
Fasdfadsfasd Aasdfads     Easdfadsf    Casdfasdf
Hasdfasdf    Baasdfasdf   Gasdfadsfads Dasdfadsf
NULL         Iasdfadsf    NULL         Jasdfasdfa
NULL         Zasdfasdf    NULL         NULL

Upvotes: 1

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