Inserting JSON array data into a MySQL database using PHP

Here I am parsing a JSON array and inserting it into a MySQL database. The JSON Array comes from my android code.

This is how my JSON array looks like:

["{custInfo=Ujwal  9975022560, rate=24000, weight=21.00000, desc=GENTS ANGTHI 22k NO STONE, makingAmt=200, vat=RS.3064.38, itemTotal=51073, sum_total=RS.156283.38, barcode=BQSP78BB, net_rate=24200, date=2015-11-30, invoiceNo=1, bill_type=Invoice}",
"{custInfo=Ujwal  9975022560, rate=24000, weight=21.00000, desc=GENTS ANGTHI 22k NO STONE, makingAmt=200, vat=RS.3064.38, itemTotal=51073, sum_total=RS.156283.38, barcode=BQSP78BB, net_rate=24200, date=2015-11-30, invoiceNo=1, bill_type=Invoice}",
"{custInfo=Ujwal  9975022560, rate=24000, weight=21.00000, desc=GENTS ANGTHI 22k NO STONE, makingAmt=200, vat=RS.3064.38, itemTotal=51073, sum_total=RS.156283.38, barcode=BQSP78BB, net_rate=24200, date=2015-11-30, invoiceNo=1, bill_type=Invoice}"]

This is my php code to parse and insert the data.

custInfo;
    $rate =     $inv->rate;
    $weight=    $inv->weight;
    $desc=      $inv->desc;
    $makingAmt= $inv->makingAmt;
    $vat=       $inv->vat;
    $itemTotal= $inv->itemTotal;
    $sum_total= $inv->sum_total;
    $barcode=   $inv->barcode;
    $net_rate=  $inv->net_rate;
    $date=      $inv->date;
    $invoiceNo= $inv->invoiceNo;
    $bill_type= $inv->bill_type;
    $sql = "INSERT INTO selected_items 
             (custInfo, invoiceNo, barcode, desc, 
              weight, rate, makingAmt,net_rate,
              itemTotal,vat,sum_total,bill_type,date) 
            VALUES
             ('$custInfo','$invoiceNo','$barcode','$desc',
              '$weight','$rate','$makingAmt','$net_rate',
              '$itemTotal','$vat','$sum_total','$bill_type','$date')";
    $res = mysqli_query($sql,$con);
echo $res;
    if(!$res){
        $result = new stdClass();
        $result->status = false;
        $result->msg = mysql_error();
        echo json_encode($result);
        exit;
    }
}
?>

You are open to SQL Injection. To prevent this, use prepared statements.

You also should not mix mysql_ and mysqli_ functions; always use mysqli_ (or PDO).

Having variables that are only accessed once is only useful in a limited number of cases, eg when you want to give something a nice name to increase readability. But this is not the case with your variables, so they are really not needed and actually decrease readability. Jut use $inv->custInfo etc directly. This will also severely shorten your code.

StackExchange Code Review Q#112331, answer score: 5