JSON_MERGE_PRESERVE

描述

合并两个或多个 JSON 文档并返回合并结果。

语法

JSON_MERGE_PRESERVE(json_doc, json_doc[, json_doc] ...)

说明

参数 json_doc 指定需要合并的 JSON 文档。

如果任何参数为 NULL，则返回 NULL。如果任何参数不是有效的 JSON 文档，则会报错。

JSON_MERGE_PRESERVE() 合并规则如下：

• 相邻数组合并为一个数组。

• 相邻的对象合并为一个对象。

• 标量值自动包裹为数组并且合并为数组。

• 通过将对象自动包裹为数组来合并相邻的数组和对象。

示例

SELECT JSON_MERGE_PRESERVE('[1, 2, 3]', '[true, false]');
+---------------------------------------------------+
| JSON_MERGE_PRESERVE('[1, 2, 3]', '[true, false]') |
+---------------------------------------------------+
| [1, 2, 3, true, false]                            |
+---------------------------------------------------+
1 row in set (0.001 sec)

SELECT JSON_MERGE_PRESERVE('{"name": "apple"}', '{"id": 56}');
+--------------------------------------------------------+
| JSON_MERGE_PRESERVE('{"name": "apple"}', '{"id": 56}') |
+--------------------------------------------------------+
| {"id": 56, "name": "apple"}                            |
+--------------------------------------------------------+
1 row in set (0.001 sec)

SELECT JSON_MERGE_PRESERVE('1', 'true');
+----------------------------------+
| JSON_MERGE_PRESERVE('1', 'true') |
+----------------------------------+
| [1, true]                        |
+----------------------------------+
1 row in set (0.001 sec)

SELECT JSON_MERGE_PRESERVE('[1, 2, 3]', '{"id": 56}');
+------------------------------------------------+
| JSON_MERGE_PRESERVE('[1, 2, 3]', '{"id": 56}') |
+------------------------------------------------+
| [1, 2, 3, {"id": 56}]                          |
+------------------------------------------------+
1 row in set (0.001 sec)

SELECT JSON_MERGE_PRESERVE('{ "a": 1, "b": 2, "c": 5}',  '{ "a": 3, "c": 4 }');
+-------------------------------------------------------------------------+
| JSON_MERGE_PRESERVE('{ "a": 1, "b": 2, "c": 5}',  '{ "a": 3, "c": 4 }') |
+-------------------------------------------------------------------------+
| {"a": [1, 3], "b": 2, "c": [5, 4]}                                      |
+-------------------------------------------------------------------------+
1 row in set (0.001 sec)

SELECT JSON_MERGE_PRESERVE('{ "a": 1, "b": 2 }','{ "a": 3, "c": 4 }', '{ "a": 5, "d": 6 }');
+--------------------------------------------------------------------------------------+
| JSON_MERGE_PRESERVE('{ "a": 1, "b": 2 }','{ "a": 3, "c": 4 }', '{ "a": 5, "d": 6 }') |
+--------------------------------------------------------------------------------------+
| {"a": [1, 3, 5], "b": 2, "c": 4, "d": 6}                                             |
+--------------------------------------------------------------------------------------+
1 row in set (0.001 sec)