Else will not execute is at first sight? Solution Solutions

Else will not execute is at first sight?
if ($_post["submit"]) {
$id =$_post["ITM"];
$ip =$_server["REMOTE_ADDR"];
$postdate = Date (' y-m-d h:i:s ', Time ());
$sql = "Select IP from Ipadd where ip= ' $ip '";
$result =mysql_query ($sql);
$row =mysql_fetch_array ($result);

if (mysql_num_rows ($row) < 1) {
$sql = "INSERT into Ipadd (Ip,id, postdate) VALUES (' $ip ', ' $id ', ' $postdate ')";
$res = mysql_query ($sql);

}
else{
echo "Not Empty";
}
}

?>


This will only perform the if first half, the echo "not empty" behind, and this will not be done, help to see what the problem is.
------to solve the idea----------------------
if (mysql_num_rows ($row) < 1) {

Switch

if (mysql_num_rows ($ result) < 1) {

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