MySQL5.7中新增的JSON类型的使用方法

创建表json_test:

CREATE TABLE json_test(id INT(11) AUTO_INCREMENT PRIMARY KEY,person_desc JSON)ENGINE INNODB;

插入一条记录：

INSERT INTO json_test(person_desc) VALUES ('{
"programmers": [{
"firstName": "Brett",
"lastName": "McLaughlin",
"email": "aaaa"
}, {
"firstName": "Jason",
"lastName": "Hunter",
"email": "bbbb"
}, {
"firstName": "Elliotte",
"lastName": "Harold",
"email": "cccc"
}],
"authors": [{
"firstName": "Isaac",
"lastName": "Asimov",
"genre": "sciencefiction"
}, {
"firstName": "Tad",
"lastName": "Williams",
"genre": "fantasy"
}, {
"firstName": "Frank",
"lastName": "Peretti",
"genre": "christianfiction"
}],
"musicians": [{
"firstName": "Eric",
"lastName": "Clapton",
"instrument": "guitar"
}, {
"firstName": "Sergei",
"lastName": "Rachmaninoff",
"instrument": "piano"
}]
}');

查看插入的这行JSON数据有哪些KEY：

mysql> SELECT id,json_keys(person_desc) as "keys" FROM json_test\G
*************************** 1. row ***************************
id: 1
keys: ["authors", "musicians", "programmers"]
1 row in set (0.00 sec)

可以看到里面有三个KEY，分别为authors，musicians，programmers。那现在找一个KEY把对应的值拿出来：

mysql> SELECT json_extract(AUTHORS,'$.lastName[0]') AS 'name', AUTHORS FROM
-> (
-> SELECT id,json_extract(person_desc,'$.authors[0][0]') AS "authors" FROM json_test
-> UNION ALL
-> SELECT id,json_extract(person_desc,'$.authors[1][0]') AS "authors" FROM json_test
-> UNION ALL
-> SELECT id,json_extract(person_desc,'$.authors[2][0]') AS "authors" FROM json_test
-> ) AS T1
-> ORDER BY NAME DESC\G
*************************** 1. row ***************************
name: "Williams"
AUTHORS: {"genre": "fantasy", "lastName": "Williams", "firstName": "Tad"}
*************************** 2. row ***************************
name: "Peretti"
AUTHORS: {"genre": "christianfiction", "lastName": "Peretti", "firstName": "Frank"}
*************************** 3. row ***************************
name: "Asimov"
AUTHORS: {"genre": "sciencefiction", "lastName": "Asimov", "firstName": "Isaac"}

3 rows in set (0.00 sec)

列出详细值：

mysql> SELECT
-> json_extract(AUTHORS,'$.firstName[0]') AS "firstname",
-> json_extract(AUTHORS,'$.lastName[0]') AS "lastname",
-> json_extract(AUTHORS,'$.genre[0]') AS "genre"
-> FROM
-> (
-> SELECT id,json_extract(person_desc,'$.authors[0]') AS "authors" FROM json
_test
-> ) AS T\G
*************************** 1. row ***************************
firstname: "Isaac"
lastname: "Asimov"
genre: "sciencefiction"
1 row in set (0.00 sec)

删掉authors这个KEY对应的所有对象：

mysql> UPDATE json_test SET person_desc = json_remove(person_desc,'$.authors')\G
Query OK, 1 row affected (0.01 sec)
Rows matched: 1  Changed: 1  Warnings: 0

查找对应的KEY，发现已经被删除掉：

mysql> SELECT json_contains_path(person_desc,'all','$.authors') as authors_exist
s FROM json_test\G
*************************** 1. row ***************************
authors_exists: 0
1 row in set (0.00 sec)