Question

我正在尝试查询前3位客户。我有3张桌子：

客户表（CustomerID，公司）
产品表（ProductID，ProductName，Price）
订单表（订单ID，日期，金额，客户ID）

OrderID     Date        Amount      CustomerID
19      2012-08-24  20      10043
20      2012-08-24  40      10044
21      2012-08-24  60      10044
22      2012-08-24  80      10042
23      2012-08-24  90      10043
24      2012-08-24  100     10042
25      2012-08-24  50      10041

如果你看到这张表：

10042订购价值180美元的产品
10043订购了价值110美元的产品
10044订购价值100美元的产品

如何查询此信息：

前3名客户

CustomerID  Company     Cost of Products Ordered
10042       HP      $180
10043       Acer        $110
10044       Sony        $100

目前我有这个mysql，但它没有显示我想要的方式。有人可以帮助指出我的错误吗？

$query = "SELECT 
    CustomerOrder.CustomerID, CustomerOrder.Amount, 
    Customer.Company, 
    count(CustomerOrder.Amount) as total_amount
FROM 
    `CustomerOrder` 
     INNER JOIN Customer ON Customer.CustomerID = CustomerOrder.CustomerID
GROUP BY CustomerID 
ORDER BY total_amount DESC LIMIT 3";

目前，我得到了这个：

 Top 3 Customers

CustomerID  Company         Cost of Product Ordered
10042       HP          80.00
10043       Acer            20.00
10044       Sony            40.00

我正在使用此代码显示：

$result = mysql_query($query);
$num=mysql_numrows($result);
echo "<table border='1'>
<tr>
<th>CustomerID</th>
<th>Company</th>
<th>Cost of Product Ordered</th>

</tr>";

while($row = mysql_fetch_array($result)) 
  {
  echo "<tr>";
  echo "<td>" . $row['CustomerID'] . "</td>";
  echo "<td>" . $row['Company'] . "</td>";
  echo "<td>" . $row['total_amount'] . "</td>";

  echo "</tr>";
  }
echo "</table>";

Answer 1

使用SUM代替COUNT：

SELECT 
    Customer.CustomerID,
    Customer.Company, 
    SUM(CustomerOrder.Amount) AS total_amount
FROM CustomerOrder
INNER JOIN Customer
ON Customer.CustomerID = CustomerOrder.CustomerID
GROUP BY Customer.CustomerID 
ORDER BY total_amount DESC
LIMIT 3

Answer 2

使用以下查询...我检查了它......正在运行

select ordr.CustomerID,cust.Company,(Sum(ordr.Amount)) as  'Cost of Products Ordered' from `order` ordr , customer cust where cust.CustomerID=ordr.CustomerID group by ordr.CustomerID order by Sum(ordr.Amount) desc limit 3

Mysql查询前3名客户

2 个答案: