一文详解如何在MySQL中处理JSON数据

CREATE TABLE `people` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `info` json DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

INSERT INTO `people` (`info`) VALUES 
('{"name": "John Doe", "age": 30, "address": {"street": "123 Main St", "city": "Anytown", "state": "CA"}}'),
('{"name": "Jane Smith", "age": 25, "address": {"street": "456 Elm St", "city": "Othertown", "state": "NY"}}');

-- 提取 Alice 的 email
SELECT JSON_EXTRACT(info, '$.email') AS email
FROM users
WHERE name = 'Alice';

-- 去掉引号
SELECT JSON_UNQUOTE(JSON_EXTRACT(info, '$.email')) AS email
FROM users
WHERE name = 'Alice';

-- 更新 Bob 的 email
UPDATE users
SET info = JSON_SET(info, '$.email', 'bob.newemail@example.com')
WHERE name = 'Bob';

-- 查询居住在 New York 的用户
SELECT name
FROM users
WHERE JSON_EXTRACT(info, '$.address.city') = '"New York"';

UPDATE `people` SET `info` = JSON_REPLACE(`info`, '$.address.city', 'Newtown') WHERE `id` = 1;

UPDATE `people` SET `info` = JSON_REMOVE(`info`, '$.phone') WHERE `id` = 1;

-- 统计每个城市的用户数量
SELECT JSON_EXTRACT(info, '$.address.city') AS city,
       COUNT(*) AS user_count
FROM users
GROUP BY city;

-- 创建表
CREATE TABLE hobbies (
    id INT AUTO_INCREMENT PRIMARY KEY,
    user_id INT,
    hobbies JSON
);

-- 插入数据
INSERT INTO hobbies (user_id, hobbies) VALUES
(1, '["Reading", "Swimming", "Hiking"]'),
(2, '["Cooking", "Traveling"]');

-- 查找有 "Traveling" 爱好的用户
SELECT user_id
FROM hobbies
WHERE JSON_CONTAINS(hobbies, '"Traveling"');

-- 添加虚拟列
ALTER TABLE users ADD COLUMN city VARCHAR(100) GENERATED ALWAYS AS (JSON_UNQUOTE(JSON_EXTRACT(info, '$.address.city'))) VIRTUAL;

-- 创建索引
CREATE INDEX idx_city ON users(city);