mysql php dynamic group by sql query

I am trying to get the php mysql query to return the result dynamically group by field.

For some reasons it is not working here is the code that I am using.

<?php
    $servername = "localhost";
    $username = "user";
    $password = "pass";

    try {
        $objDatabase = new PDO("mysql:host=$servername;dbname=myDB", $username, $password);
        $objDatabase->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        echo "Connected successfully";
        }
    catch(PDOException $e)
        {
        echo "Connection failed: " . $e->getMessage();
        }
?>

<?php 

//Process the GET data received from the previous page.
$custo = $_GET["Customer"];
$startdate = $_GET["fromdate"];
$enddate = $_GET["enddate"];
$stdate = date("Y-m-d", strtotime($startdate));
$endate = date("Y-m-d", strtotime($enddate));


$basequery = "SELECT cust, manu, model, serial, capacity, firmware, method, date, stime, etime, wks, result, COUNT(*) AS total FROM hdds WHERE cust = '".$custo."' and `date` >= '".$stdate."' and `date` <= '".$endate."'";

$retval = mysql_query( $basequery, $conn );
if(! $retval )
{
  die('Could not get data: ' . mysql_error());
}

?>


    <?php 

$type="capacity";
$typeQuery = $basequery." GROUP BY ".$type;
// Perform the Query
$objDbResultByType = $objDatabase->Query($typeQuery);
echo '<div id="1000" style="display: none;">';
echo "<h3>Quality Control Checked by<br></h3><strong>";
$capacity = array();
while ($row = $objDbResultByType()) {
    echo $row['capacity']. " = " .$row['total'];
    echo "<br><strong>";
$result = "{ label: \"".$row['capacity']."\", y: " .$row['total']." },";
array_push($capacity,$result);
}
//echo $result;
$lastIndex = count($capacity)-1;
$lastValue = $capacity[$lastIndex];
$testedby[$lastIndex] = rtrim($lastValue, ',');

//Echo the capacity from array to the monitor screen.
foreach ($capacity as $result){
echo $result, '<br>';
}


    ?>

The code above gives me blank screen.

However if I run this query on mysql it returns the data, there is no problem with the query.

mysql> SELECT cust, manu, model, serial, capacity, firmware, method, date, stime, etime, wks, result, COUNT(*) AS total from hdds where cust = 'Imran-ABC' and date >= '2015-08-01' and '2015-09-14' group by date;
+-----------+------------------------------------------+------------+----------+-----------------------------+----------+--------+------------+----------+----------+------+-----------+-------+
| cust      | manu                                     | model      | serial   | capacity                    | firmware | method | date       | stime    | etime    | wks  | result    | total |
+-----------+------------------------------------------+------------+----------+-----------------------------+----------+--------+------------+----------+----------+------+-----------+-------+
| ABC | Seagate Barracuda 7200.7 and 7200.7 Plus | ST340014AS | 5MQ3DJPM | 40000000000 bytes [40.0 GB] | 8.12     | zero   | 2015-08-26 | 18:56:29 | 18:56:29 | 89   | Succeeded |     1 |
| ABC | Seagate Barracuda 7200.7 and 7200.7 Plus | ST340014AS | 5MQ3DJPM | 40000000000 bytes [40.0 GB] | 8.12     | zero   | 2015-09-01 | 18:56:29 | 18:56:29 | 89   | Succeeded |    27 |
| ABC | Seagate Barracuda 7200.7 and 7200.7 Plus | ST340014AS | 5MQ3DJPM | 40000000000 bytes [40.0 GB] | 8.12     | zero   | 2015-09-02 | 20:04:19 | 20:04:19 | 36   | Succeeded |     2 |
+-----------+------------------------------------------+------------+----------+-----------------------------+----------+--------+------------+----------+----------+------+-----------+-------+
3 rows in set, 1 warning (0.00 sec)

mysql>

Can someone please help what I am doing wrong and why this is not working?

Thanks well in advance for your help.