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Note: Since we don't have any documented differences between our implementation of JSON functions and Oracle's, here and further I will assume they are supposed to be result-compatible.
|
MariaDB 10.2
|
MariaDB [test]> select JSON_MERGE(NULL,JSON_OBJECT('foo', 1));
|
+----------------------------------------+
|
| JSON_MERGE(NULL,JSON_OBJECT('foo', 1)) |
|
+----------------------------------------+
|
| [null, {"foo": 1}] |
|
+----------------------------------------+
|
1 row in set (0.00 sec)
|
|
MySQL 5.7
|
MySQL [test]> select JSON_MERGE(NULL,JSON_OBJECT('foo', 1));
|
+----------------------------------------+
|
| JSON_MERGE(NULL,JSON_OBJECT('foo', 1)) |
|
+----------------------------------------+
|
| NULL |
|
+----------------------------------------+
|
1 row in set (0.00 sec)
|
It is also documented in MySQL manual:
https://dev.mysql.com/doc/refman/5.7/en/json-modification-functions.html#function_json-merge
Returns NULL if any argument is NULL
|