非空的变量，表示未定义的变量

Question

Please check out the below code.

        $key = $_SESSION['order_nums'];
        $sqll = "SELECT * FROM `money` WHERE `order` = :key";
        $qq=$con->prepare($sqll);
        $qq->bindvalue(":key", $key);
        $qq->execute();


        $excel2 = PHPExcel_IOFactory::createReader('Excel2007');
        $excel2 = $excel2->load('nTest.xlsx'); // Empty Sheet
        $excel2->setActiveSheetIndex(0);
        $worksheet = $excel2->getActiveSheet();

        $Cno = '7';
        $COno = '7';
        $MSno = '7';
        $CHno = '7';
        $ALno = '7';


        while($fdata=$qq->fetch(PDO::FETCH_ASSOC))
        {   

                $totalCost += $fdata['cost'];


                /*
            $worksheet
                ->setCellValue('A' . $Cno++, $fdata['code'])
                ->setCellValue('D' . $COno++, $fdata['cost'])
                ->setCellValue('E' . $MSno++, $fdata['time'])
                ->setCellValue('F' . $CHno++, $fdata['hourly'])
                ->setCellValue('G' . $ALno++, $fdata['ot']);*/




        }

Ok, so the part of the code where it says $totalCost += $fdata['cost'] is saying its a undefined variable. Yet the code below it that I commented out.. If I uncomment it, it works perfect.

Answer 1

you didn't define $totalCost variable before using it, so you should define it outside while loop $totalCost = 0;

$totalCost = 0;
while($fdata=$qq->fetch(PDO::FETCH_ASSOC))
        {   

                $totalCost += $fdata['cost'];


                /*
            $worksheet
                ->setCellValue('A' . $Cno++, $fdata['code'])
                ->setCellValue('D' . $COno++, $fdata['cost'])
                ->setCellValue('E' . $MSno++, $fdata['time'])
                ->setCellValue('F' . $CHno++, $fdata['hourly'])
                ->setCellValue('G' . $ALno++, $fdata['ot']);*/




        }

because this line $totalCost += $fdata['cost']; means $totalCost = $totalCost + $fdata['cost']; and in this case it didn't find the var $totalCost