iOS Question b4a -> php mysql error

<?PHP
    function connection()
    {
        $con = mysqli_connect(************);  
      
        mysqli_set_charset('utf8',$con);
      
        return $con;
    }
  
    function my_sql_load_wert($tabelle, $index, $indexwert, $suche)
    {
        $con = connection();
      
        $query = mysqli_query($con, "SELECT `".$suche."` FROM `".$tabelle."` WHERE `".$index."` = '".mysqli_real_escape_string($con,$indexwert)."'");
                              
        while($row = mysqli_fetch_assoc($query))
        {
            return $row[$suche];
        }
      
        return $query;
    }
  
    function my_sql_load_wert2($tabelle, $index, $indexwert, $index2, $indexwert2, $suche)
    {
        $con = connection();
  
        $query = mysqli_query($con, "SELECT `".$suche."` FROM `".$tabelle."` WHERE `".$index."` = '".mysqli_real_escape_string($con,$indexwert)."' AND `".$index2."` = '".mysqli_real_escape_string($con,$indexwert2)."'");
  
        while($row = mysqli_fetch_assoc($query))
        {
            return $row[$suche];
        }
  
        return $query;
    }
      
    function my_sql_update_wert($tabelle, $index, $indexwert, $update, $updatewert)
    {
        $con = connection();
      
        mysqli_query($con, "UPDATE `".$tabelle."` SET `".$update."` = '".mysqli_real_escape_string($con,$updatewert)."' WHERE `".$index."` = '".mysqli_real_escape_string($con, $indexwert)."'");
      
        return true;
    }
  
    function my_sql_new_wert($tabelle, $index, $indexwert)
    {
        $con = connection();
      
        $st = mysqli_query("INSERT INTO `".$tabelle."` (`".$index."`) VALUES ('".mysqli_real_escape_string($con,$indexwert)."')");
      
        return mysqli_insert_id($con);
    }
  
    function my_sql_exists_wert($tabelle, $index, $indexwert)
    {
        $con = connection();
      
        $st = mysqli_query($con, "SELECT `".$index."` FROM `".$tabelle."` WHERE `".$index."` = '".mysqli_real_escape_string($con,$indexwert)."'");
        $arr = mysqli_fetch_assoc($st);
      
        return count($arr) > 0;
    }
  
    function my_sql_exists_wert2($tabelle, $index, $indexwert, $index2, $indexwert2)
    {
        $con = connection();
      
        $st = mysqli_query($con, "SELECT `".$index."` FROM `".$tabelle."` WHERE `".$index."` = '".$indexwert."' AND `".$index2."` = '".$indexwert2."'");
        $arr = mysqli_fetch_assoc($st);
      
        return count($arr) > 0;
    }
  
    function my_sql_array_count($tabelle, $suche)
    {
        $con = connection();
      
        $st = mysqli_query($con, "SELECT `".$suche."` FROM `".$tabelle."`");
        $arr = mysqli_fetch_assoc($st);
      
        return count($arr);
    }
?>

    function setPro($username, $password, $secID, $rID, $appID)
    {
        if($secID != "***************")
        {
            return "0";
        }
      
        if(pruefeRID($rID))
        {
            $userID = my_sql_load_wert("users", "email", $username, "id");
            $id = my_sql_new_wert("buy_data", "receipt", $rID);
            my_sql_update_wert("buy_data", "id", $id, "userID", $userID);
            my_sql_update_wert("buy_data", "id", $id, "valid", "true");
            my_sql_update_wert("buy_data", "id", $id, "type", $appID);

            return "1";
        }else{
            return "3";
        }
    }