Miss_kun的专栏

MySQL自5.7之后开始支持json类型，相应的解析函数主要是json_extract(); 查询sql版本：select version(); JSON_EXTRACT()函数用于从JSON中提取元素，例如： 列名：info {"Info1":[[{"id":1,"name":"aaa","grade":["{\"china\":100,\"engine\":[\"95\"],\"match\":[\"99\"]}"]}]]} select json_extract(info, '$.Info1')

Caused by: java.sql.SQLException: null,  message from server: "Host 'DESKTOP-BOV5JBI' is not allowed to connect to this MySQL server"1. 改表法。mysql -u root -pmysql>use mysql;mysql>update user set ...

1、改表法 更改 "mysql" 数据库里的 "user" 表里的 "host" 项，从"localhost"改称"%" 2、授权法 GRANT ALL PRIVILEGES ON *.* TO 'myuser'@'%' IDENTIFIED BY 'mypassword' WITH GRANT OPTION; 3、如果开启了防火墙，需要关闭防火墙，或者开放3306...