MySQL中查询和操作JSON类型的数据的方法及常见踩坑记录

CREATE TABLE product (
    id INT PRIMARY KEY AUTO_INCREMENT,
    name VARCHAR(100) NOT NULL,
    attr JSON COMMENT '商品扩展JSON属性'
);
-- 插入测试数据
INSERT INTO product(name, attr) VALUES 
('手机', '{"color":"黑色","price":3999,"tags":["旗舰","5G"],"detail":{"weight":"200g","screen":"6.7英寸"}}'),
('耳机', '{"color":"白色","price":299,"tags":["蓝牙","降噪"],"detail":{"weight":"8g","screen":null}}');

-- 查询商品名称、颜色、价格
SELECT 
    name,
    attr->>'$.color' AS color,
    attr->>'$.price' AS price
FROM product;

SELECT name, attr->>'$.detail.weight' AS weight FROM product;

-- 获取tags数组第0个元素
SELECT name, attr->>'$.tags[0]' AS tag1 FROM product;

-- 等价 attr->>'$.color'
SELECT JSON_UNQUOTE(JSON_EXTRACT(attr, '$.color')) FROM product;

-- 查询颜色为黑色的商品
SELECT name FROM product WHERE attr->>'$.color' = '黑色';
-- 查询价格大于1000
SELECT name FROM product WHERE attr->>'$.price' > 1000;

-- 查询tags数组里面包含"降噪"的商品
SELECT name FROM product 
WHERE JSON_SEARCH(attr, 'one', '降噪', null, '$.tags') IS NOT NULL;

SELECT JSON_KEYS(attr) FROM product;

-- 方式1：直接字符串
INSERT INTO product(name,attr) VALUES ('平板','{"color":"灰色","price":2499}');
-- 方式2：函数构造，不用手动写引号，不容易出错
INSERT INTO product(name,attr) VALUES (
'手表',
JSON_OBJECT("color","银色","price",1299,"tags",JSON_ARRAY("智能","防水"))
);

UPDATE product
SET attr = JSON_SET(attr, '$.color', '深空灰', '$.stock', 100)
WHERE id = 1;

UPDATE product
SET attr = JSON_REPLACE(attr, '$.price', 3699)
WHERE id = 1;

UPDATE product
SET attr = JSON_INSERT(attr, '$.stock', 200)
WHERE id = 1;

UPDATE product
SET attr = JSON_ARRAY_APPEND(attr, '$.tags', '快充')
WHERE id = 1;

UPDATE product
SET attr = JSON_ARRAY_INSERT(attr, '$.tags[0]', '新品')
WHERE id = 1;

-- 删除stock字段
UPDATE product
SET attr = JSON_REMOVE(attr, '$.stock')
WHERE id = 1;

-- 删除数组下标1的元素
UPDATE product
SET attr = JSON_REMOVE(attr, '$.tags[1]')
WHERE id = 1;

-- 创建生成列，提取color字段
ALTER TABLE product ADD COLUMN color VARCHAR(50) GENERATED ALWAYS AS (attr->>'$.color') STORED;
-- 建立索引
CREATE INDEX idx_product_color ON product(color);