[Merovingian]

Does anyone know how to check if a database holds an e-mail address , so that a user that signs up for a newsletter doesnt add the same email twice to the database, and if so an error statement for the e-mail address in the database can be echoed unto the page so the user can see that their e-mail address is already in the database.

[NeverMind]

there are 2 methods to achive this .
one is to make the 'email' field in the database as a unique index , so if someone tried to add the same email, mysql will generate a 'duplicated entry' error ..
the other way is to check upon the provied mail address by useing a SELECT query which will check, mysql_num_rows() gave a number > 0 , you generate the error :

PHP Code:

$provided_email=trim($_POST['email']);//this will get the email from a from using POST method..



$check=mysql_query("SELECT email FROM table_1 WHERE email='$provided_email'")or

die(mysql_error());



$num=mysql_num_rows($check);



if ( $num > 0 ) {

 echo'E-mail address you provided is already in database !';

 die();

} else {

//COMPLETE SCRIPT HERE..

}