unsigned: 无符号(非负) comment: 注释# 删mysql>drop table student2;## 删除用户mysql>drop user wsh1@'localhost';# 改## 修改表名mysql>show tables;+---+|Tables_in_www|+---+|student3|+---+1rowinset(0.00sec)mysql>alter table student3renamestu;Query OK,0rows affected(0.12sec)mysql>sho...