Fetching single data returns error - php

Question

I'm trying to fetch couple of single data in my server database but this is throwing some errors. The incoming data is correct. The search function just don't get completed.
Here's the code:
<?php
if($_SERVER['REQUEST_METHOD']=='POST'){
define('HOST','xxxxxxxxxxx');
define('USER','xxxxxxxxxxxx');
define('PASS','xxxxxxxxx');
define('DB','xxxxxxxxxx');
$con = mysqli_connect(HOST,USER,PASS,DB);
$post_id = $_POST['id'];
$buyer_mobile = $_POST['mobile'];
$buyer_name = $_POST['name'];
$sql = "select mobile from flatowner where id='$post_id'";
$res = mysqli_query($con,$sql);
$owner_mobile = $row['mobile'];
$sql = "select name from user where mobile='$owner_mobile'";
$r = mysqli_query($con,$sql);
$owner_name = $row['name'];
$sql = "INSERT INTO flat_booking (post_id,owner_mobile,owner_name,buyer_mobile,buyer_name) VALUES ('$post_id','$owner_mobile','$owner_name','$buyer_mobile','$buyer_name')";
if(mysqli_query($con,$sql)){
echo "Success";
}
else{
echo "error";
}
mysqli_close($con);
}else{
echo 'error1';
}
What am I doing wrong here? Maybe this:
$owner_mobile = $row['mobile'];
Thanks in advance!

Answer 1

create table flatower and add mobile column
$post_id = 1;
$sql = "select mobile from flatowner where id='$post_id'";
$res = mysql_query($con,$sql);
$row = mysql_fetch_array($res);
$owner_mobile = $row[0]['mobile'];

Answer 2

Your problem is this line:
$owner_mobile = $row['mobile'];
You have not created the $row variable. For this you would need to do something such as:
Do this first:
<?php
$row = array();
while ($result = mysqli_fetch_assoc($res))
{
$row[] = $result;
}
?>
This allows you to do this:
<?php
foreach ($row as $r)
{
var_dump($r); print "<br />"; // One row from the DB per var dump
}
?>