ผมอยากรู้ว่า 2 ตารางที่ select ขึ้นมา จะเอาผลรวมของทั้ง สอง ตาราง มา คูณ หรือ หารกัน ทำไมไม่ได้ ครับ

$spp1="SELECT   count(order_generation)  AS  V_TOTAL_new , SUM(order_size)   AS   V_TOTAL_new1     FROM    genneration_size_new   WHERE   order_generation='ASD' or  order_generation='CSD'  or  order_generation='HRG'   or  order_generation='LBG'    or  order_generation='LSD'  or  order_generation='OBD' or  order_generation='PFR' or  order_generation='RAL'  or  order_generation='WSG'    or  order_generation='$hdata'     GROUP   BY     order_generation";
$qu1=mysql_query($spp1);
while($arr1=mysql_fetch_array($qu1)){
$order_generation=$arr1['order_generation'];
echo   $data_1[] = $arr1[V_TOTAL_new]."   /    "."<br>";
echo   $data_2[] = $arr1[V_TOTAL_new1]."<br>";
  $data_sum_1=$arr1[V_TOTAL_new]  /  $arr1[V_TOTAL_new1]."<br>";
echo  $data_sum_1."<br>";
}
echo "------------------------------------------------------------------------------------"."<br>";

$spp="SELECT   count(order_generation)  AS  V_TOTAL1 , SUM(size_new)   AS   V_TOTAL     FROM    genneration_size   WHERE   
order_generation='ASD' or  order_generation='CSD'  or  order_generation='HRG'   or  order_generation='LBG'    or  order_generation='LSD'  or  order_generation='OBD' or  order_generation='PFR' or  order_generation='RAL'  or  order_generation='WSG'    or  order_generation='$hdata'     GROUP   BY     order_generation";
$qu=mysql_query($spp);
while($arr=mysql_fetch_array($qu)){
$order_generation=$arr['order_generation'];
   $data1= $arr[V_TOTAL1]."<br>";
echo    $data2 = $arr[V_TOTAL]."<br>";
echo    $data_sum[]=$arr[V_TOTAL] * $data_sum_1."<br>";
}