How to search through in JSON array on SQL - mysql

Question

I'm using MySQL 5.6.43 and trying to search through in JSON array in a table. My JSON in MySQL database is like this:
[
{
"Name": "AAA",
"CountryCode": "AFG",
"District": "Kabol",
"Population": 1780000
},
{
"Name": "BBB",
"CountryCode": "AFG",
"District": "Qandahar",
"Population": 237500
},
{
"Name": "CCC",
"CountryCode": "USD",
"District": "Qandahar",
"Population": 237500
}
]
I want to take the just AFG CountryCode's. So my result should be like this:
[
{
"Name": "AAA",
"CountryCode": "AFG",
"District": "Kabol",
"Population": 1780000
},
{
"Name": "BBB",
"CountryCode": "AFG",
"District": "Qandahar",
"Population": 237500
}
]
How can I achieve that?

Answer 1

SELECT test.data, JSON_ARRAYAGG(JSON_OBJECT('Name',jsontable.Name,
'CountryCode',jsontable.CountryCode,
'District',jsontable.District,
'Population',jsontable.Population)) filtered
FROM test,
JSON_TABLE(test.data,
'$[*]' COLUMNS (Name VARCHAR(255) PATH '$.Name',
CountryCode VARCHAR(255) PATH '$.CountryCode',
District VARCHAR(255) PATH '$.District',
Population VARCHAR(255) PATH '$.Population')) jsontable
WHERE jsontable.CountryCode = 'AFG'
GROUP BY test.data;
fiddle
In MySQL 5.6 you must use string functions - JSON is not implemented in this version yet:
SELECT CONCAT('[', GROUP_CONCAT('{', SUBSTRING_INDEX(SUBSTRING_INDEX(SUBSTRING_INDEX(test.data, '}', nums.num), '}', -1), '{', -1), '}'), ']') filtered
FROM test
CROSS JOIN (SELECT 1 num UNION SELECT 2 UNION SELECT 3 UNION SELECT 4) nums
WHERE LOCATE('"CountryCode":"AFG"', SUBSTRING_INDEX(SUBSTRING_INDEX(REPLACE(test.data, ' ', ''), '}', nums.num), '}', -1))
GROUP BY test.data
fiddle
If source array may contain more than 4 objects per value then expand nums subquery.
Restriction: Neither key nor value to be searched must contain a space.