In MariaDB, JSON_DEPTH() is a built-in function that allows you to check the depth of a JSON document.
It accepts the JSON document as an argument, and returns the maximum depth of the document.
functions
MariaDB JSON_EXISTS() Explained
In MariaDB, JSON_EXISTS() is a built-in function that allows you to check whether a value exists at a specified path in the JSON document.
It accepts the JSON document as an argument, and returns 1 if the path is found, and 0 if it’s not.
The MariaDB documentation states that the function “determines whether a specified JSON value exists in the given data”. However, the function doesn’t actually appear to check for a given value. It’s probably more accurate to say that it determines whether a specified path exists, or that a value exists at the specified path.
For checking that the actual value exists, you can use the JSON_CONTAINS() function.
MariaDB JSON_QUERY() Explained
In MariaDB, JSON_QUERY() is a built-in function that returns an object or array from a JSON document, based on the path provided.
It’s similar to the JSON_VALUE() function, except that it returns an object or array instead of a scalar (JSON_VALUE() returns a scalar).
MariaDB JSON_VALUE() Explained
In MariaDB, JSON_VALUE() is a built-in function that returns a scalar value from a JSON document. More specifically, it returns the scalar specified by the path provided.
MariaDB JSON_MERGE_PATCH() Explained
In MariaDB, JSON_MERGE_PATCH() is a built-in function that merges two or more JSON documents and returns the result.
The JSON_MERGE_PATCH() function is an RFC 7396-compliant replacement for the JSON_MERGE() function, which has been deprecated.
MariaDB JSON_MERGE_PRESERVE() Explained
In MariaDB, JSON_MERGE_PRESERVE() is a built-in function that merges two or more JSON documents and returns the result.
JSON_MERGE_PRESERVE() is a synonym for JSON_MERGE(), which has been deprecated. To avoid future issues, you should use the JSON_MERGE_PATCH() function instead. The JSON_MERGE_PATCH() function is an RFC 7396-compliant replacement for JSON_MERGE().
MariaDB JSON_MERGE() Explained
In MariaDB, JSON_MERGE() is a built-in function that merges two or more JSON documents and returns the result.
The JSON_MERGE() function has been deprecated, and to avoid future issues, you should use the JSON_MERGE_PATCH() function instead. The JSON_MERGE_PATCH() function is an RFC 7396-compliant replacement for JSON_MERGE().
MariaDB JSON_EXTRACT() Explained
In MariaDB, JSON_EXTRACT() is a built-in function that extracts data from a JSON document, based on a given path or paths.
It can return single values and multiple values. If a single value is matched, a single value is returned. If multiple values are matched, then those values are returned in an array.
MariaDB JSON_DETAILED() Explained
In MariaDB, JSON_DETAILED() is a built-in function that takes a JSON document, and returns it in a more human-readable format.
This is sometimes referred to as prettifying the document. It’s similar to MySQL’s JSON_PRETTY() function.
For the opposite effect (i.e. to condense a JSON document down), use the JSON_COMPACT() function.
MariaDB JSON_COMPACT() Explained
In MariaDB, JSON_COMPACT() is a built-in function that removes all unnecessary spaces from a JSON document, so that it’s as short and compact as possible, and returns the result.
This can be handy for when you need to store JSON data in a database column, and you don’t want the JSON documents to use up any more space than is necessary.
For the opposite effect (i.e. to prettify a JSON document by adding indents and spreading it over multiple lines), use the JSON_DETAILED() function.