Cannot retrieve the last row from mysql - php

Question

I seem to be having trouble getting any response from this script whatsoever. No error messages, nothing...As you can see, what I am trying to do is insert into table "yum", echo the last entry, then use that last entry to insert in a separate table. What am I doing wrong and why aren't there any error messages?
<?php
$b= $_GET["sto"];
$pb= $_GET["usto"];
$sql = "INSERT INTO yum(vara, varb)
VALUES('" . $b . "', '" . $pb . "')";
$hostname_Database = "blocked";
$database_Database = "blocked";
$username_Database = "blocked";
$password_Database = "blocked";
$mysqli = new mysqli($hostname_Database, $username_Database, $password_Database, $database_Database);
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$result = $mysqli->query($sql);
if ($result) {
echo "ha";
$sql = $mysqli->query("SELECT vara FROM yum ORDER BY vara DESC LIMIT 1");
if($sql === FALSE) {
echo "ahahahahah";
die(mysql_error()); // TODO: better error handling
}
while($row = mysql_fetch_array($sql))
{
echo $row['vara'];
}
//$row = $result->fetch_assoc();
$sql = "INSERT INTO disco(varb, vara)
VALUES( '" . $item . "', {$row['vara']})";
$result = $mysqli->query($sql);
if ($result) {
etc...
}
}
?>

Answer 1

You are using
while($row = mysql_fetch_array($sql))
{
echo $row['vara'];
}
Here when $row becomes null for last entry so use foreach but as you are getting only one row so instead of all the while loop just use
$row = mysql_fetch_array($sql);
Also either use just mysql_* or mysqli_*
Here is the full code
$mysqli = mysqli_connect($hostname_Database, $username_Database, $password_Database, $database_Database);
if (mysqli_connect_errno($mysqli)) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$result = $mysqli_query($con,$sql);
if ($result) {
echo "ha";
$sql = $mysqli_query("SELECT vara FROM yum ORDER BY vara DESC LIMIT 1");