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CREATE TABLE test (id INT, json_value JSON);
INSERT INTO test VALUES
(1, '{ "2": { "model": "Test Model" }, "3": { "model": "Test Model" } }'),
(2, '{ "4": { "model": "Test Model" }, "2": { "model": "Test Model" } }'),
(3, '{ "1": { "model": "Test Model" }, "4": { "model": "Test Model" } }'),
(4, '{ "2": { "model": "Test Model" } }');
Records: 4 Duplicates: 0 Warnings: 0
SELECT jsontable.`key`, COUNT(*) `count`
FROM test
CROSS JOIN JSON_TABLE(JSON_KEYS(test.json_value),
'$[*]' COLUMNS (`key` INT PATH '$')) jsontable
GROUP BY jsontable.`key`
| key | count |
|---|---|
| 2 | 3 |
| 3 | 1 |
| 4 | 2 |
| 1 | 1 |