MYSQL query WHERE php array

Updated version of your code to put out an error message on the query if there is one. Also sanitises the input

if (is_array($_POST['select']))
{
    $c = array_map('array_map_callback', $_POST['select']);


    $result = mysqli_query($con, 'SELECT item_name, item_number FROM item WHERE item_number IN ("'.implode('","', $c).'")') OR die(mysqli_error($con));

    echo "



";
    while($row = mysqli_fetch_array($result))
    {
        echo "";

        echo "";
        echo "";
        echo "";
    }
    echo "
    
    
item name
    
item number
    
" . $row['item_name'] . "
" . $row['item_number'] . "
";
    mysqli_close($con);
}
else
{
    echo "No items selected";

}

function array_map_callback($a)
{
  global $con;
  return mysqli_real_escape_string($con, $a);
}

?>

Hopefully this should put out the message of what is wrong with the query.