PHP + MySQL taking a 3rd variable - php

Question

I have a C# code and a PHP that gets info I send from C#.
So I need to have such code:
<?php
$link = mysqli_connect('localhost','root','');
$database = mysqli_select_db($link,'serial');
$serial = $_GET['serial'];
$hwid = $_GET['hwidin'];
$sql = "SELECT * FROM serial WHERE serial = '". mysqli_real_escape_string($link,$serial) ."'" ;
$result = $link->query($sql);
/*
0 = Wrong HWID
1 = HWID is correct
2 = HWID left empty
3 = No serial with that key
*/
if(strlen($hwid) < 1)
{
echo "2";
}
else
{
if ($result->num_rows > 0) {
while($row = $result->fetch_assoc()) {
if (strlen($row['hwid']) > 1)
{
if ($hwid != $row['hwid'])
{
echo "0";
}
else
{
echo "1";
}
}
else
{
$sql = "UPDATE serial SET hwid='$hwid' WHERE serial='$serial'";
echo "1";
if(mysqli_query($link, $sql))
{
echo $row['hwid'];
}
else
{
echo "ERROR: Could not able to execute $sql. " . mysqli_error($link);
}
}
}
}
else
{
echo "3";
}
}
So what I want to do is add some checking, for example:
if ($result->num_rows > 0) {
while($row = $result->fetch_assoc()) {
if (strlen($row['hwid']) > 1)
{
if ($hwid != $row['hwid'])
{
echo "0";
}
else
{
echo "1";
}
If echo "1" {
$sql = "SELECT time FROM serial Where serial = '". mysqli_real_escape_string($link,$serial) ."'" ;
$result = $link->query($sql);
if $result > 1 {
echo "55";
}
I need somehow to combine it with hwid checker and serial checker.
I want to check "time" column variable and use > < 1 to decide what to echo.