This article brings you the basic JSON operations (code examples) of MySQL5.7. It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.
JSON basic operations of MySQL5.7
MySQL has supported JSON format data since version 5.7, and the operation is very convenient.
Creating a table
When creating a new table, the field type can be directly set to the json type. For example, if we create a table:
mysql> CREATE TABLE `test_user`(`id` INT PRIMARY KEY AUTO_INCREMENT, `name` VARCHAR(50) NOT NULL, `info` JSON);
json type field can be NULL
Insert data:
mysql> INSERT INTO test_user(`name`, `info`) VALUES('xiaoming','{"sex": 1, "age": 18, "nick_name": "小萌"}');The field of json type must be a valid json string
You can use the JSON_OBJECT() function to construct a json object:
mysql> INSERT INTO test_user(`name`, `info`) VALUES('xiaohua', JSON_OBJECT("sex", 0, "age", 17));Use the JSON_ARRAY() function Construct a json array:
mysql> INSERT INTO test_user(`name`, `info`) VALUES('xiaozhang', JSON_OBJECT("sex", 1, "age", 19, "tag", JSON_ARRAY(3,5,90)));Now view the data in the test_user table:
mysql> select * from test_user;
+----+-----------+--------------------------------------------+
| id | name | info |
+----+-----------+--------------------------------------------+
| 1 | xiaoming | {"age": 18, "sex": 1, "nick_name": "小萌"} |
| 2 | xiaohua | {"age": 17, "sex": 0} |
| 3 | xiaozhang | {"age": 19, "sex": 1, "tag": [3, 5, 90]} |
+----+-----------+--------------------------------------------+
3 rows in set (0.04 sec)Query
Expression: The object is a json column->'$.key ', the array is json column->'$.key[index]'
mysql> select name, info->'$.nick_name', info->'$.sex', info->'$.tag[0]' from test_user; +-----------+---------------------+---------------+------------------+ | name | info->'$.nick_name' | info->'$.sex' | info->'$.tag[0]' | +-----------+---------------------+---------------+------------------+ | xiaoming | "小萌" | 1 | NULL | | xiaohua | NULL | 0 | NULL | | xiaozhang | NULL | 1 | 3 | +-----------+---------------------+---------------+------------------+ 3 rows in set (0.04 sec)
is equivalent to: the object is JSON_EXTRACT(json column, '$.key'), the array is JSON_EXTRACT(json column, ' $.key[index]')
mysql> select name, JSON_EXTRACT(info, '$.nick_name'), JSON_EXTRACT(info, '$.sex'), JSON_EXTRACT(info, '$.tag[0]') from test_user; +-----------+-----------------------------------+-----------------------------+--------------------------------+ | name | JSON_EXTRACT(info, '$.nick_name') | JSON_EXTRACT(info, '$.sex') | JSON_EXTRACT(info, '$.tag[0]') | +-----------+-----------------------------------+-----------------------------+--------------------------------+ | xiaoming | "小萌" | 1 | NULL | | xiaohua | NULL | 0 | NULL | | xiaozhang | NULL | 1 | 3 | +-----------+-----------------------------------+-----------------------------+--------------------------------+ 3 rows in set (0.04 sec)
However, I saw that "Xiaomeng" above has double quotes. This is not what we want. We can use the JSON_UNQUOTE function to remove the double quotes
mysql> select name, JSON_UNQUOTE(info->'$.nick_name') from test_user where name='xiaoming'; +----------+-----------------------------------+ | name | JSON_UNQUOTE(info->'$.nick_name') | +----------+-----------------------------------+ | xiaoming | 小萌 | +----------+-----------------------------------+ 1 row in set (0.05 sec)
You can also use the operator directly ->>
mysql> select name, info->>'$.nick_name' from test_user where name='xiaoming'; +----------+----------------------+ | name | info->>'$.nick_name' | +----------+----------------------+ | xiaoming | 小萌 | +----------+----------------------+ 1 row in set (0.06 sec)
Of course attributes can also be used as query conditions
mysql> select name, info->>'$.nick_name' from test_user where info->'$.nick_name'='小萌'; +----------+----------------------+ | name | info->>'$.nick_name' | +----------+----------------------+ | xiaoming | 小萌 | +----------+----------------------+ 1 row in set (0.05 sec)
It is worth mentioning that you can use virtual columns to Quickly query specified attributes of JSON type.
Create virtual columns:
mysql> ALTER TABLE `test_user` ADD `nick_name` VARCHAR(50) GENERATED ALWAYS AS (info->>'$.nick_name') VIRTUAL;
Note that using the operator ->>
is the same as the normal column query:
mysql> select name,nick_name from test_user where nick_name='小萌'; +----------+-----------+ | name | nick_name | +----------+-----------+ | xiaoming | 小萌 | +----------+-----------+ 1 row in set (0.05 sec)
Update
Use JSON_INSERT() to insert new values, but will not overwrite existing values
mysql> UPDATE test_user SET info = JSON_INSERT(info, '$.sex', 1, '$.nick_name', '小花') where id=2;
Look at the results
mysql> select * from test_user where id=2;
+----+---------+--------------------------------------------+-----------+
| id | name | info | nick_name |
+----+---------+--------------------------------------------+-----------+
| 2 | xiaohua | {"age": 17, "sex": 0, "nick_name": "小花"} | 小花 |
+----+---------+--------------------------------------------+-----------+
1 row in set (0.06 sec)Use JSON_SET() to insert new values and overwrite existing values
mysql> UPDATE test_user SET info = JSON_INSERT(info, '$.sex', 0, '$.nick_name', '小张') where id=3;
Look at the results
mysql> select * from test_user where id=3;
+----+-----------+---------------------------------------------------------------+-----------+
| id | name | info | nick_name |
+----+-----------+---------------------------------------------------------------+-----------+
| 3 | xiaozhang | {"age": 19, "sex": 1, "tag": [3, 5, 90], "nick_name": "小张"} | 小张 |
+----+-----------+---------------------------------------------------------------+-----------+
1 row in set (0.06 sec)Use JSON_REPLACE() to only replace existing values Value
mysql> UPDATE test_user SET info = JSON_REPLACE(info, '$.sex', 1, '$.tag', '[1,2,3]') where id=2;
Look at the result
mysql> select * from test_user where id=2;
+----+---------+--------------------------------------------+-----------+
| id | name | info | nick_name |
+----+---------+--------------------------------------------+-----------+
| 2 | xiaohua | {"age": 17, "sex": 1, "nick_name": "小花"} | 小花 |
+----+---------+--------------------------------------------+-----------+
1 row in set (0.06 sec)You can see that the tag is not updated
Delete
Use JSON_REMOVE() to delete JSON elements
mysql> UPDATE test_user SET info = JSON_REMOVE(info, '$.sex', '$.tag') where id=1;
Look at the results
mysql> select * from test_user where id=1;
+----+----------+----------------------------------+-----------+
| id | name | info | nick_name |
+----+----------+----------------------------------+-----------+
| 1 | xiaoming | {"age": 18, "nick_name": "小萌"} | 小萌 |
+----+----------+----------------------------------+-----------+
1 row in set (0.05 sec)This article is all over here. For more other exciting content, you can follow PHP Chinese Net's MySQL tutorial video column!
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