https://blog.boychai.xyz/index.php/archives/61/ zh-CN SQL分类类别全称概述DDLData Definition Language数据定义语言，用来定义数据库对象(数据库，表，字段)DMLData Manipulation Language数据操作... Thu, 01 Jan 1970 00:00:00 +0000 Thu, 01 Jan 1970 00:00:00 +0000