Using the
Jayway JsonPath evaluator[
^], it seems that
$.`key`
will not match anything in your input document.
From a quick read of the
JSONPath syntax[
^], it seems that this is looking for a property called
key
on your JSON object. There is no such property.
The same problem applies to
$.`value`
- the is no property called
value
on the object.
I suspect you will need to use
JSON_KEYS[
^] to extract the keys, and
$.*
to extract the values. However, I don't have access to a MariaDB instance to test this. Based on the documentation, I suspect you will still end up with a single row in your result table.