Question

I cant quite think about how to do this with mysql and php. Basically I want to be able to submit data into a mysql database but before it is inserted, it will check to see if that entry already exists.

$guid=$_POST['guid'];
$name=$_POST['name'];
//Username
$user="webhost";
//Password
$pass="*******";
//IP To Host
$ip="***********";
//Database
$db="dayz2";
//Table
$table="whitelist";

//Database Connection
$con=@mysql_connect("$ip", "$user", "$pass")
            or die(mysql_error());

//Select Database
$dbcon=@mysql_select_db($db, $con)
            or die(mysql_error());
$dupesql = "SELECT * FROM $table where (name = '$name' AND guid = '$guid')";

$duperaw = mysql_query($dupesql);

if (mysql_num_rows($duberaw) > 0) {
  echo "Entry Already Exists";
}
else {
//Query Data Into Whitelist Table
$sql="INSERT INTO $table (name, guid) VALUES ('$name', '$guid')";

//Submit Data into Whitelist Table
$result=@mysql_query($sql, $con) or die(mysql_error());
}
?>

Answer 1

You can do it in another way, instead of:

submit data into a mysql database but before it is inserted, it will
check to see if that entry already exists.

You can do:

INSERT data into a mysql database if not existed, else ignore them

Something like :

INSERT IGNORE INTO table
INSERT IGNORE INTO yourtablename
SET fieldname = 'blah'
,..