how to use insert and select statement together

Question

can any one tell me how to use insert and select  statement together with in a same table in  mysql.my query is this

 

INSERT INTO `test` ( `id` , `UName` , `Password` )
SELECT '', 'Ahmed', 'Ahmed123'
FROM test

 

but it will return more than one rows inserted.but when i try this 

 

INSERT INTO `test` ( `id` , `UName` , `Password` )
SELECT '', 'Ahmed', 'Ahmed123'
FROM test

where  id = 2;

 

it will return 0 row inserted .

my php code is this

$sql="INSERT into alumnireg(id,Fname,Mname,Lname,Email,Password)
select '','$fname','$mname','$lname','$email','$pass'
from alumnireg where Email = '$email' AND Password = '$pass'";

$result =mysql_query($sql);
confirm_query($result);