Mariadb query and extract JSON data - json

Question

I have a MaraiDB (10.2.14) database containing a table where in one column JSON data is stored.
I'm puzzled as how to extract data from this column.
Example Data
SELECT 1 AS ID
, '[{"name":"x","score":2},{"name":"y", "score":8},{"name":"z","score":3}]' AS REPLY
UNION ALL
SELECT 2 AS ID
, '[{"name":"x","score":5},{"name":"y", "score":4},{"name":"z","score":3}]' AS REPLY
UNION ALL
SELECT 3 AS ID
, '[{"name":"x","score":2},{"name":"y", "score":2},{"name":"z","score":6}]' AS REPLY
UNION ALL
SELECT 4 AS ID
, '[{"name":"x","score":5},{"name":"y", "score":8},{"name":"z","score":6}]' AS REPLY
So how would I find all entries having "name":"x" and a "score":5. Additionally I need to get the "score" value of the "name":"y" of that entry.
My current dirty approach is
WITH JT1 AS (
SELECT 1 AS ID
, '[{"name":"x","score":2},{"name":"y", "score":8},{"name":"z","score":3}]' AS REPLY
UNION ALL
SELECT 2 AS ID
, '[{"name":"x","score":5},{"name":"y", "score":4},{"name":"z","score":3}]' AS REPLY
UNION ALL
SELECT 3 AS ID
, '[{"name":"x","score":2},{"name":"y", "score":2},{"name":"z","score":6}]' AS REPLY
UNION ALL
SELECT 4 AS ID
, '[{"name":"x","score":5},{"name":"y", "score":8},{"name":"z","score":6}]' AS REPLY
)
SELECT ID
, REGEXP_REPLACE(
REGEXP_REPLACE( EXTRACTED, '^.*"y",\\s', '')
, '[,\\]].*$', '') AS Y
, EXTRACTED
FROM (
SELECT ID
, JSON_EXTRACT(REPLY, '$[*].name','$[*].score') EXTRACTED
FROM JT1
) JT2
WHERE EXTRACTED RLIKE '"x", 5\\b'
;
So I first extract "name" and "score" which gives me column data like ["x", 5, "y", 4, "z", 3]. With that I do some nasty REGEXP search & replaces.
I feel there must be a better way.
I tried using COLUMN_CREATE, but "COLUMN_CREATE" seems not to be able to accept the result from JSON_EXTRACT as input. Now that I think about it, this seems logical as "name" and "score" here are properly ordered, but can I be sure it's always that sequence?
Can anyone give me a hint how to do this better?

Answer 1

If I understand what you need, a query like the following may be useful:
WITH `JT1` AS (
SELECT 1 AS `ID`
, '[{"name":"x","score":2},{"name":"y", "score":8},{"name":"z","score":3}]' AS `REPLY`
UNION ALL
SELECT 2 AS `ID`
, '[{"name":"x","score":5},{"name":"y", "score":4},{"name":"z","score":3}]' AS `REPLY`
UNION ALL
SELECT 3 AS `ID`
, '[{"name":"x","score":2},{"name":"y", "score":2},{"name":"z","score":6}]' AS `REPLY`
UNION ALL
SELECT 4 AS `ID`
, '[{"name":"x","score":5},{"name":"y", "score":8},{"name":"z","score":6}]' AS `REPLY`
)
SELECT
`ID`,
`REPLY`,
JSON_VALUE(
`REPLY`,
JSON_UNQUOTE(
REPLACE(
JSON_SEARCH(`REPLY`, 'one', 'y', NULL, '$[*].name'),
'name',
'score'
)
)
) `"name":"y"`
FROM
`JT1`
WHERE
JSON_VALUE(
`REPLY`,
JSON_UNQUOTE(
REPLACE(
JSON_SEARCH(`REPLY`, 'one', 'x', NULL, '$[*].name'),
'name',
'score'
)
)
) = 5;
See dbfiddle.