12、MySQL菜鸟教程
http://www.runoob.com/mysql/mysql-data-types.html
怎样备份/还原MySQL数据库 之 MySQL Workbench
https://jingyan.baidu.com/article/870c6fc32ea48cb03fe4beaa.html
MySQL之——GROUPBY分组取字段最大值
https://www.2cto.com/database/201701/591542.html
https://www.cnblogs.com/linJie1930906722/p/6036714.html
https://www.cnblogs.com/acm-bingzi/p/msqlLimit.html