Mysql使用函数json_extract处理Json类型数据的方法实例

-- 创建测试表
CREATE TABLE `tab_json` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '主键id',
  `data` json DEFAULT NULL COMMENT 'json字符串',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- 新增数据
-- {"Tel": "132223232444", "name": "david", "address": "Beijing"}
-- {"Tel": "13390989765", "name": "Mike", "address": "Guangzhou"}
INSERT INTO `testdb`.`tab_json`(`id`, `data`) VALUES (1, '{\"Tel\": \"132223232444\", \"name\": \"david\", \"address\": \"Beijing\"}');
INSERT INTO `testdb`.`tab_json`(`id`, `data`) VALUES (2, '{\"Tel\": \"13390989765\", \"name\": \"Mike\", \"address\": \"Guangzhou\"}');
INSERT INTO `testdb`.`tab_json`(`id`, `data`) VALUES (3, '{"success": true,"code": "0","message": "","data": {"name": "jerry","age": "18","sex": "男"}}');
INSERT INTO `testdb`.`tab_json`(`id`, `data`) VALUES (4, '{"success": true,"code": "1","message": "","data": {"name": "tome","age": "30","sex": "女"}}');

-- 查询
select * from tab_json;

-- json_extract
select json_extract('{"name":"Zhaim","tel":"13240133388"}',"$.tel");
select json_extract('{"name":"Zhaim","tel":"13240133388"}',"$.name");

-- 对tab_json表使用json_extract函数
select json_extract(data,'$.name') from tab_json;

#如果查询没有的key,那么是可以查询,不过返回的是NULL.
select json_extract(data,'$.name'),json_extract(data,'$.Tel') from tab_json;  
select json_extract(data,'$.name'),json_extract(data,'$.tel') from tab_json;  
select json_extract(data,'$.name'),json_extract(data,'$.address') from tab_json;

-- 条件查询
select json_extract(data,'$.name'),json_extract(data,'$.Tel') from tab_json where json_extract(data,'$.name') = 'Mike';  

-- 嵌套json查询
select * from tab_json where json_extract(data,'$.success') = true;  
select json_extract(data,'$.data') from tab_json where json_extract(data,'$.success') = true;  
-- 查询data对应json中key为name的值
select json_extract( json_extract(data,'$.data'),'$.name') from tab_json where json_extract(data,'$.code') = "1";  
select json_extract( json_extract(data,'$.data'),'$.name'),json_extract( json_extract(data,'$.data'),'$.age') from tab_json where json_extract(data,'$.code') = "0";  

-- 性能验证 , 通过验证全部都是全表扫描，使用场景：数据量不大json字符串较大则可以采用，数据量较大不建议使用。
explain select * from tab_json where json_extract(data,'$.success') = true;  
explain select json_extract(data,'$.data') from tab_json where json_extract(data,'$.success') = true;  
-- 查询data对应json中key为name的值
explain select json_extract( json_extract(data,'$.data'),'$.name') from tab_json where json_extract(data,'$.code') = "1";  
explain select json_extract( json_extract(data,'$.data'),'$.name'),json_extract( json_extract(data,'$.data'),'$.age') from tab_json where json_extract(data,'$.code') = "0";