mysql 5.7中支持json了

在mysql 5.7中，可以支持json了，比如一个表：
mysql> create table my_hash (id int not null primary key, doc json);
Query OK, 0 rows affected (0.59 sec)

mysql> show tables;
+------------------+
| Tables_in_test   |
+------------------+
| my_hash_0        |
| my_hash_1        |
| my_hash_2        |
| my_hash_3        |
| pre_forum_post_6 |
| pre_forum_post_7 |
| t_json           |
+------------------+
7 rows in set (0.00 sec)

插入一些记录
  mysql> insert into my_hash (id, doc)
    ->    values (1, '{"key1": "row1_1", "key2": "row1_2"}');
Query OK, 1 row affected (0.02 sec)

mysql> insert into my_hash (id, doc)
    ->    values (2, '{"key1": "row2_1", "key2": "row2_2"}');
Query OK, 1 row affected (0.02 sec)

mysql> insert into my_hash (id, doc)
    ->    values (3, '{"key1": "row3_1", "key2": "row3_2"}');
Query OK, 1 row affected (0.02 sec)

mysql> insert into my_hash (id, doc)
    ->    values (4, '{"key1": "row4_1", "key2": "row4_2"}');
Query OK, 1 row affected (0.02 sec)

下面开始使用json
  mysql> select doc->"$.key1" from my_hash where id =2;
+---------------+
| doc->"$.key1" |
+---------------+
| "row2_1"      |
+---------------+
1 row in set (0.00 sec)

mysql> select json_extract(doc,"$.key1") from my_hash where id =2;
+------------------------------+
| json_extract(doc , '$.key1') |
+------------------------------+
| "row2_1"                     |
+------------------------------+
1 row in set (0.00 sec)

甚至可以update语句中用json了
  mysql> update my_hash set doc = json_set(doc, "$.newkey", 'new value')
    -> where id = 2;
Query OK, 1 row affected (0.02 sec)
Rows matched: 1 Changed: 1 Warnings: 0

mysql> select * from my_hash where id = 2;
+----+-------------------------------------------------------------+
| id | doc |
+----+-------------------------------------------------------------+
| 2  | {"key1": "row2_1", "key2": "row2_2", "newkey": "new value"} |
+----+-------------------------------------------------------------+
1 row in set (0.00 sec)