添加行时出现PHP错误 - PHP Error while adding the rows

我想将所有行中的金额相加。这是代码。请帮帮我。

$tot1=mysql_query("select SUM(Amount) from wp_product_details"); 
while($row1 = mysql_fetch_array($tot1))
{
echo $row1['Amount'];
}

将查询更改为使用$row1[] 的金额

$tot1=mysql_query("select SUM(Amount) as Amount from wp_product_details");

或者更改$row1[]语法

while($row1 = mysql_fetch_array($tot1))
{
echo $row1['SUM(Amount)'];
}

试试这个代码

 $tot1=mysql_query("select SUM(Amount) as amount from wp_product_details"); 
    while($row1 = mysql_fetch_array($tot1))
    {
    echo $row1['amount'];
    }