How to split array data to next row in Postgres - sql

Question

I have data in a table. I want to split the array data into separated rows.
create table test1 (
_id serial,
questionId character varying (50),
answer character varying (50),
subquestionId character varying (50),
subquestionAnswer character varying (50),
isActive character varying (1)
);
INSERT INTO test1 (questionid,answer,subquestionid,subquestionanswer,isactive)
values
('question 1','true','[100,101,102]','[[true],[false],[true]]','1'),('question 2','false','[101,106]','[[false],[true]]','1');
_id
questionid
answer
subquestionid
subquestionanswer
isactive
1
question 1
true
[100,101,102]
[[true],[false],[true]]
1
2
question 2
false
[101,106]
[[false],[true]]
1
Output should be needed.

Answer 1

As explained in this answer you may convert the string representation of arrays to real arrays with translate and cast. (As commented you should not store the arrays as strings)
select
_id,
answer,
translate(subquestionid, '[]', '{}')::int[] subquestionid,
translate(subquestionanswer, '[]', '{}')::boolean[] subquestionanswer,
isactive
from test1;
result
_id|answer|subquestionid|subquestionanswer |isactive|
---+------+-------------+-----------------------+--------+
1|true |{100,101,102}|{{true},{false},{true}}|1 |
2|false |{101,106} |{{false},{true}} |1 |
To split the arrays use unnest and keep the order using WITH ORDINALITY AS
Finaly limit the result to rows with the identical ordinality, which I assume is the expected result, though differing from your output
with t as (
select
_id,
answer,
translate(subquestionid, '[]', '{}')::int[] subquestionid,
translate(subquestionanswer, '[]', '{}')::boolean[] subquestionanswer,
isactive
from test1
)
select
t._id,
t.answer,
a.subquestionid,
b.subquestionanswer,
t.isactive
from t
cross join lateral unnest(subquestionid) WITH ORDINALITY AS a(subquestionid, nr)
cross join lateral unnest(subquestionanswer) WITH ORDINALITY AS b(subquestionanswer, nr)
where a.nr = b.nr
_id|answer|subquestionid|subquestionanswer|isactive|
---+------+-------------+-----------------+--------+
1|true | 100|true |1 |
1|true | 101|false |1 |
1|true | 102|true |1 |
2|false | 101|false |1 |
2|false | 106|true |1 |

Answer 2

You can do it using string_to_array to convert string to array, and generate multiple rows from single one as follows :
SELECT *
FROM (
SELECT t._id, t.questionid, t.answer, REGEXP_REPLACE(theAnswer, '\[|\]|\[\[|\]\]', '') as subquestionanswer, t.isactive
FROM test1 t,
unnest(string_to_array(subquestionanswer, '],[')) theAnswer
) S
this how it should be :
SELECT t._id, t.questionid, t.answer, s.subquestionid, t.subquestionanswer, t.isactive
FROM (
SELECT _id, questionid, answer, REGEXP_REPLACE(subquestionans, '\[|\]|\[\[|\]\]', '') as subquestionanswer, isactive,
ROW_NUMBER () OVER (
ORDER BY _id
)
FROM test1,
unnest(string_to_array(subquestionanswer, '],[')) subquestionans
) t
inner join (
SELECT _id , REGEXP_REPLACE(subquestion, '\[|\]', '') as subquestionid,
ROW_NUMBER () OVER (
ORDER BY _id
)
FROM test1 ,
unnest(string_to_array(subquestionid, ',')) subquestion
) s on s.ROW_NUMBER = t.ROW_NUMBER;
Demo here : https://dbfiddle.uk/b1w3RyCJ

Answer 3

Thank you for the reply!
Below table data needs to convert into screenshot format. Earlier there was one bracket one value, now there are one bracket two values. (subquestionid-153). I have extract this data from Talend.
create table test1 (_id serial, questionId character varying (50), answer character varying (50), subquestionId character varying (50), subquestionAnswer character varying (225), isActive character varying (1));
INSERT INTO test1 (questionid,answer,subquestionid,subquestionanswer,isactive) values ('question 1','true','[100,101,102]','[[true],[false],[true]]','1'),('question 2','false','[101,106]','[[false],[true]]','1');