How to update JSON data type column in MySQL 5.7.10?

Question

I recently started using MySQL 5.7.10 and I really like the native JSON data type.

But I have a problem when updating JSON type value.

question:

The following is the table format, here I want to add 1 key to the t1 table in the data column. Now I have to get the value modify it and update the table. So it involves an additional SELECT statement.

I can insert it like this

INSERT INTO t1 values ('{"key2":"value2"}', 1);

mysql> select * from t1;
+--------------------+------+
| data               | id   |
+--------------------+------+
| {"key1": "value1"} |    1 |
| {"key2": "value2"} |    2 |
| {"key2": "value2"} |    1 |
+--------------------+------+
3 rows in set (0.00 sec)

mysql>Show create table t1;


+-------+-------------------------------------------------------------

-------------------------------------------------------+
| Table | Create Table                                                                                                       |
+-------+--------------------------------------------------------------------------------------------------------------------+
| t1    | CREATE TABLE `t1` (
  `data` json DEFAULT NULL,
  `id` int(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+-------+--------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

Is there any solution?

Answer 1

Now with MySQL 5.7.22, it is very simple and straightforward to update an entire piece of json (multiple key values, even nested) in a single query, like this:

update t1 set data = 
JSON_MERGE_PATCH(`data`, '{"key2": "I am ID2", "key3": "I am ID3"}') where id = 2;

Hope it helps visiting this page and looking for a "better" JSON_SET :) More information about JSON_MERGE_PATCH can be found here: https://dev.mysql .com/doc/refman/5.7/en/json-modification-functions.html#function_json-merge-patch

Answer 2

Thanks to @wchiquito for pointing me in the right direction. I solved this problem. This is how I do it.

mysql> select * from t1;
+----------------------------------------+------+
| data                                   | id   |
+----------------------------------------+------+
| {"key1": "value1", "key2": "VALUE2"}   |    1 |
| {"key2": "VALUE2"}                     |    2 |
| {"key2": "VALUE2"}                     |    1 |
| {"a": "x", "b": "y", "key2": "VALUE2"} |    1 |
+----------------------------------------+------+
4 rows in set (0.00 sec)

mysql> update t1 set data = JSON_SET(data, "$.key2", "I am ID2") where id = 2;
Query OK, 1 row affected (0.04 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> select * from t1;
+----------------------------------------+------+
| data                                   | id   |
+----------------------------------------+------+
| {"key1": "value1", "key2": "VALUE2"}   |    1 |
| {"key2": "I am ID2"}                   |    2 |
| {"key2": "VALUE2"}                     |    1 |
| {"a": "x", "b": "y", "key2": "VALUE2"} |    1 |
+----------------------------------------+------+
4 rows in set (0.00 sec)

mysql> update t1 set data = JSON_SET(data, "$.key3", "I am ID3") where id = 2;
Query OK, 1 row affected (0.07 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> select * from t1;
+------------------------------------------+------+
| data                                     | id   |
+------------------------------------------+------+
| {"key1": "value1", "key2": "VALUE2"}     |    1 |
| {"key2": "I am ID2", "key3": "I am ID3"} |    2 |
| {"key2": "VALUE2"}                       |    1 |
| {"a": "x", "b": "y", "key2": "VALUE2"}   |    1 |
+------------------------------------------+------+
4 rows in set (0.00 sec)

---

edit: If you want to add an array, use JSON_ARRAY like

update t1 set data = JSON_SET(data, "$.key4", JSON_ARRAY('Hello','World!')) where id = 2;