select name,pass from tbAdmin where name='admin' and pass='123456'
输入用户名:' or 1='1
SQL变成下面这个样子:
select name,pass from tbAdmin where name='' or 1='1' and pass='123456'
1='1' 永远为真,所以就验证通过了。。。
select name,pass from tbAdmin where name='admin' and pass='123456'