array or object member selector step.

For example:

select json_extract(@json_doc, '$**.price');

will select all object members in the document that are named price, while

select json_extract(@json_doc, '$**[2]');

will select the second element in each of the arrays present in the document.

Compatibility
-------------

MariaDB's JSONPath syntax supports a subset of JSON Path's definition in the
SQL Standard. The most notable things not supported are the strict mode and
filters.

MariaDB's JSONPath is close to MySQL's JSONPath. The wildcard step ( ** ) is a
non-standard extension that has the same meaning as in MySQL. The difference
between MariaDB and MySQL's JSONPath is: MySQL doesn't allow one to specify
the mode explicitly (but uses lax mode implicitly).

URL: https://mariadb.com/kb/en/jsonpath-expressions/https://mariadb.com/kb/en/jsonpath-expressions/