How to query expanded json content in db2 - json

Question

Since version 11, DB2 supports json functions and json value query. I was trying to follow the documentation but could not figure out how to expand a json object into multiple rows. Would like to know if it's possible at all in DB2.
Example:
The JSON object looks like this:
{
"content":{
"key_1": {
"text": "sample",
"label": "l1"
},
"key_2": {
"text": "sample2",
"label": "l2"
},
...
}
}
and the table looks like this:
|id|json|
|--|----|
|1 | '{...}'|
|2 | '{...}'|
I want to query this table:
|id|text|label|
|--|----|-----|
|1 |sample|l1|
|1 |sample2|l2|
...
I tried
SELECT JSON_VALUE(json, 'strict $.content.*.text' RETURNING CHAR(10)) AS text,
JSON_VALUE(json, 'strict $.content.*.label' RETURNING CHAR(10)) AS label
FROM table
but I got NULL for all the rows.
Any insights are appreciated. Thank you!

Answer 1

I belive you need to do something like this
SELECT I, T.*
FROM
TABLE(VALUES('{
"content":{
"key_1": {
"text": "sample",
"label": "l1"
},
"key_2": {
"text": "sample2",
"label": "l2"
}
}
}')) AS D(JSON)
, TABLE(VALUES(1),(2),(3)) AS A(I)
, JSON_TABLE(D.JSON, 'strict $'
COLUMNS(
TEXT VARCHAR(80) PATH '$.content.key_' || i || '.text'
, LABEL VARCHAR(80) PATH '$.content.key_' || i || '.label'
)
ERROR ON ERROR) AS T
WHERE T.TEXT is NOT NULL
which will give you
I|TEXT |LABEL
-|-------|------
1|sample |l1
2|sample2|l2
The A table in the above will need as many rows as you have key_ entries in the JSON