找到重复值的总和？

Question

我想找到重复的ISBN作为Distinct，它们的总数量为sum。

我希望 ISBN = 9789 总数量为 509 且 ISBN = 978944 总数量 194

我使用的代码如下所示

`array('fields'=> array('ERPBookdetail.id','ERPBookdetail.item','ERPBookdetail.book_id','ERPBookdetail.isbn','ERPBookdetail.title',
                                'ERPBookdetail.class','ERPBookdetail.subject','ERPBookdetail.medium','ERPBookdetail.board','ERPBookdetail.edition'
                                ,'ERPBookdetail.db_type','ERPBookdetail.price','ERPOrderDetail.item','ERPOrder.order_id','ERPBookdetail.qty','SUM(ERPBookdetail.qty) as total_quantity'),
                'group' => array('ERPBookdetail.isbn'),
               'order'=>'total_quantity DESC',
              'joins' => array(
                        array(
                    'table' => 'orders',
                    'alias' => 'ERPOrder',
                    'type' => 'INNER',
                        'conditions' => array('OR' => array(
                                                        array('ERPOrder.confirmation' => 1),array('ERPOrder.confirmation' => 'Yes'),
                                    )),
                            ),
        array('table' => 'order_details',
        'alias' => 'ERPOrderDetail',
        'type' => 'INNER',
        'conditions' =>array('ERPOrderDetail.item = ERPBookdetail.item','ERPOrder.order_id = ERPOrderDetail.order_id'),)),)
);`

Answer 1

只需

即可在mysql中执行此操作

    select isbn, sum(qty) as qty from table group by isbn

如果您不想更改mysql查询，那么在php中就可以通过这种方式

   for($isbn_rec = 0 ; $isbn_rec < count($your_outputarray_from_query); $isbn_rec++)
   {
      $new_array[$your_outputarray_from_query['isbn']]['qty'] += $your_outputarray_from_query['qty'];
      // if any isbn records comes again then it will be sum up with older isbn number
   }

您将获得最终数组，如下所示

  array('9789'=>    array('qty'=>'509')
'978944'=> array('qty'->'194')
  )