$query="select * from huge_table where conditions joins etc";
$result=mysql_query($query);
$price_p=array();
$price_s=array();
while($row=mysql_fetch_array($result,MYSQL_ASSOC)){
   if($row['price']=="P"){
       array_push($price_p,$row['price']);
   }
   if($row['price']=="S"){
       array_push($price_s,$row['price']);
   }
}

SELECT * FROM sales_item d
 
 
 
JOIN (SELECT STR_TO_DATE('2007-09-30', '%Y-%m-%d') st_date) v
 
 
 
JOIN item_store f on f.item_no=d.item_no AND f.store_id = d.store_id
 
 
 
JOIN item_sellprice_store a on f.item_no=a.item_no AND f.store_id = a.store_id
 
 
 
JOIN item b on f.item_no=b.item_no
 
 
 
JOIN item_supplier c on b.item_no=c.item_no AND b.supplier_no=c.supplier_no
 
 
 
JOIN item_sellprice_storegroup g on a.batch_id=g.batch_id
 
 
 
 
 
JOIN store k on f.store_id =k.store_id
 
 
 
WHERE d.store_id = '011'
 
 
 
AND (f.item_status ='A' OR f.item_status ='O')
 
 
 
AND a.price_type='P'
 
 
 
AND a.effective_start_date < v.st_date < a.effective_end_date
 
 
 
AND d.sale_date = v.st_date
 
 
 
ORDER BY d.category_code, a.sell_gst, a.item_no ;