MySQL query con variables PHP

[andresdzphp]

Algo así:

Código PHP:

<?php
 
//MySQL Database Connect 
mysql_connect("localhost", "*******", "*********")  or die("Unable to connect to MySQL"); 
mysql_select_db('tu_base_de_datos_aqui');
 
//get data from form  
$email=$_POST['email']; 
 
//Count coincidences on database 
$sql = "SELECT COUNT(*) existe FROM pressmails WHERE email='$email'"; 
$result = mysql_query($sql) or die (mysql_error());
$reg = mysql_fetch_assoc($result);
 
//If there are more than 0 coincidences the user is registered  
//otherwise not registered 
if($reg['existe']){  
    echo "The user is registered"; 
} else {  
    echo "The user is not registered"; 
}  
 
//Close database connection 
mysql_close();