send message if user is in the database, reject if not - php

Question

if (isset($submit)) {
$getusers = mysql_query("SELECT * FROM register");
while($getrows = mysql_fetch_array($getusers)) {
$users = $getrows['username'];
if ($touser == $users) {
echo "$users";
$send = $_GET['send'];
if ($send == $one) {
$query = mysql_query(
"INSERT INTO mailtbl VALUES
(
'', '$touser', '$fromuser', '$subject',
'$message', '0', '0', '1', '$date', '$rand'
)"
);
$query2 = mysql_query(
"INSERT INTO mailtbl_admin VALUES
(
'', '$touser', '$fromuser', '$subject',
'$message', '0', '0', '1', '$date', '$rand'
)"
);
$echo = "Message successfully sent.";
}
} else {
$echo = "There is no such user with the name of '$touser'";
}
}
echo "$echo";
}
I am trying to write code that accepts the message to send to another user if the recipient is in my database. The problem is that I think my condition (if ($touser == $users) is wrong. $touser refers to my $_POST['recipient'] in my form and $users refer to the users in the database.
Could someone please review my code to ensure I'm on the right track?

Answer 1

Instead of looping through all the users in your table, why don't you instead add a WHERE statement in your SQL command like this:
"SELECT * FROM register WHERE username = '" . $touser . "'"
If you get results send the message. If you get no results, display the 'no such user' message.
Also, if you are having trouble evaluating $touser to $user, try outputting the contents of $touser to make sure it's what you think it is.
print_r($touser);