JSON_MERGE_PATCH(json_doc, json_doc[, json_doc] ...)

MySQL 8.4

Syntax

MYSQL

SELECT JSON_MERGE_PATCH('[1, 2]', '[true, false]');
+---------------------------------------------+
| JSON_MERGE_PATCH('[1, 2]', '[true, false]') |
+---------------------------------------------+
| [true, false]                               |
+---------------------------------------------+

SELECT JSON_MERGE_PATCH('{"name": "x"}', '{"id": 47}');
+-------------------------------------------------+
| JSON_MERGE_PATCH('{"name": "x"}', '{"id": 47}') |
+-------------------------------------------------+
| {"id": 47, "name": "x"}                         |
+-------------------------------------------------+

SELECT JSON_MERGE_PATCH('1', 'true');
+-------------------------------+
| JSON_MERGE_PATCH('1', 'true') |
+-------------------------------+
| true                          |
+-------------------------------+

SELECT JSON_MERGE_PATCH('[1, 2]', '{"id": 47}');
+------------------------------------------+
| JSON_MERGE_PATCH('[1, 2]', '{"id": 47}') |
+------------------------------------------+
| {"id": 47}                               |
+------------------------------------------+

SELECT JSON_MERGE_PATCH('{ "a": 1, "b":2 }',
     >     '{ "a": 3, "c":4 }');
+-----------------------------------------------------------+
| JSON_MERGE_PATCH('{ "a": 1, "b":2 }','{ "a": 3, "c":4 }') |
+-----------------------------------------------------------+
| {"a": 3, "b": 2, "c": 4}                                  |
+-----------------------------------------------------------+

SELECT JSON_MERGE_PATCH('{ "a": 1, "b":2 }','{ "a": 3, "c":4 }',
     >     '{ "a": 5, "d":6 }');
+-------------------------------------------------------------------------------+
| JSON_MERGE_PATCH('{ "a": 1, "b":2 }','{ "a": 3, "c":4 }','{ "a": 5, "d":6 }') |
+-------------------------------------------------------------------------------+
| {"a": 5, "b": 2, "c": 4, "d": 6}                                              |
+-------------------------------------------------------------------------------+

Examples

Example

Performs an RFC 7396 compliant merge of two or more JSON documents and returns the merged result, without preserving members having duplicate keys. Raises an error if at least one of the documents passed as arguments to this function is not valid.

MYSQL

SELECT JSON_MERGE_PATCH('[1, 2]', '[true, false]');
+---------------------------------------------+
| JSON_MERGE_PATCH('[1, 2]', '[true, false]') |
+---------------------------------------------+
| [true, false]                               |
+---------------------------------------------+

SELECT JSON_MERGE_PATCH('{"name": "x"}', '{"id": 47}');
+-------------------------------------------------+
| JSON_MERGE_PATCH('{"name": "x"}', '{"id": 47}') |
+-------------------------------------------------+
| {"id": 47, "name": "x"}                         |
+-------------------------------------------------+

SELECT JSON_MERGE_PATCH('1', 'true');
+-------------------------------+
| JSON_MERGE_PATCH('1', 'true') |
+-------------------------------+
| true                          |
+-------------------------------+

SELECT JSON_MERGE_PATCH('[1, 2]', '{"id": 47}');
+------------------------------------------+
| JSON_MERGE_PATCH('[1, 2]', '{"id": 47}') |
+------------------------------------------+
| {"id": 47}                               |
+------------------------------------------+

SELECT JSON_MERGE_PATCH('{ "a": 1, "b":2 }',
     >     '{ "a": 3, "c":4 }');
+-----------------------------------------------------------+
| JSON_MERGE_PATCH('{ "a": 1, "b":2 }','{ "a": 3, "c":4 }') |
+-----------------------------------------------------------+
| {"a": 3, "b": 2, "c": 4}                                  |
+-----------------------------------------------------------+

SELECT JSON_MERGE_PATCH('{ "a": 1, "b":2 }','{ "a": 3, "c":4 }',
     >     '{ "a": 5, "d":6 }');
+-------------------------------------------------------------------------------+
| JSON_MERGE_PATCH('{ "a": 1, "b":2 }','{ "a": 3, "c":4 }','{ "a": 5, "d":6 }') |
+-------------------------------------------------------------------------------+
| {"a": 5, "b": 2, "c": 4, "d": 6}                                              |
+-------------------------------------------------------------------------------+

Example 2

For an explanation and example of the differences between this function and JSON_MERGE_PRESERVE(), see JSON_MERGE_PATCH() compared with JSON_MERGE_PRESERVE().

MYSQL

SELECT JSON_MERGE_PATCH('{"a":1, "b":2}', '{"b":null}');
+--------------------------------------------------+
| JSON_MERGE_PATCH('{"a":1, "b":2}', '{"b":null}') |
+--------------------------------------------------+
| {"a": 1}                                         |
+--------------------------------------------------+

Example 3

JSON_MERGE_PATCH() performs a merge as follows:

MYSQL

SELECT JSON_MERGE_PATCH('{"a":{"x":1}}', '{"a":{"y":2}}');
+----------------------------------------------------+
| JSON_MERGE_PATCH('{"a":{"x":1}}', '{"a":{"y":2}}') |
+----------------------------------------------------+
| {"a": {"x": 1, "y": 2}}                            |
+----------------------------------------------------+

Example 4

If the first argument is not an object, the result of the merge is the same as if an empty object had been merged with the second argument.

MYSQL

SET @x = '{ "a": 1, "b": 2 }',
     >     @y = '{ "a": 3, "c": 4 }',
     >     @z = '{ "a": 5, "d": 6 }';

SELECT  JSON_MERGE_PATCH(@x, @y, @z)    AS Patch,
        JSON_MERGE_PRESERVE(@x, @y, @z) AS Preserve\G
*************************** 1. row ***************************
   Patch: {"a": 5, "b": 2, "c": 4, "d": 6}
Preserve: {"a": [1, 3, 5], "b": 2, "c": 4, "d": 6}