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考虑一个定义为的 xml 文件：

<?xml version="1.0"?>
<sports>
    <teams>
    <team tno="t100">
            <tname>Knights</tname>
            <city>London</city>
        </team>
        <team tno="t200">
            <tname>Dukes</tname>
            <city>Surrey</city>
        </team> 
        <team tno="t300">
            <tname>Kings</tname>
            <city>Leeds</city>
        </team>     
    </teams>

    <players>
    <player pid="p501">
            <pname>Simon</pname>
            <city>London</city>
        </player>
        <player pid="p502">
            <pname>Andrew</pname>
            <city>Birmingham</city>
        </player>
        <player pid="p503">
            <pname>Mike</pname>
            <city>London</city>
        </player>       
    </players>


    <parts>
        <part pno="801">            
            <pname>Right Gloves</pname>
            <price>8.99</price>
        </part>
        <part pno="901">            
            <pname>Left Gloves</pname>
            <price>9.99</price>
        </part>
        <part pno="851">            
            <pname>Left Pad</pname>
            <price>33.00</price>
        </part>
        <part pno="951">            
            <pname>Right Pad</pname>
            <price>43.00</price>
        </part>
    </parts>

    <orders>    
        <order ono="61" playerNum="p501" team="t200" >
            <kits>
                <kit>
                    <pNum>801</pNum>
                    <qty>11</qty>
                </kit>
            </kits>
        </order>
        <order ono="62" playerNum="p501" team="t100" >
            <kits>
                <kit>
                    <pNum>901</pNum>
                    <qty>12</qty>
                </kit>

            </kits>
        </order>

        <order ono="63" playerNum="p502" team="t300" >
            <kits>
                <kit>
                    <pNum>851</pNum>
                    <qty>9</qty>
                </kit>

            </kits>
        </order>

        <order ono="64" playerNum="p503" team="t300" >
            <kits>
                <kit>
                    <pNum>951</pNum>
                    <qty>16</qty>
                </kit>

            </kits>
        </order>


        <order ono="65" playerNum="p503"  team="t200" >
            <kits>
                <kit>
                    <pNum>801</pNum>
                    <qty>12</qty>
                </kit>
                <kit>
                    <pNum>901</pNum>
                    <qty>16</qty>
                </kit>
                <kit>
                    <pNum>851</pNum>
                    <qty>13</qty>
                </kit>
            </kits>
        </order>

    </orders>
</sports>

我尝试运行的查询是获取某个订单的总定价（比如订单 65）。BaseX 中的查询是：

let $d:=doc("sports.xml")
let $o:=$d/sports/orders/order[@ono=65]
let $p:=$d/sports/parts/part
for $k in $o/kits/kit 
return <OrderCost>
({$k/qty})*({$p[@pno=$k/pNum]/price})
</OrderCost>

我的输出：

<OrderCost>
(<qty>12</qty>)*(<price>8.99</price>)
</OrderCost>
<OrderCost>
(<qty>16</qty>)*(<price>9.99</price>)
</OrderCost>
<OrderCost>
(<qty>13</qty>)*(<price>33.00</price>)
</OrderCost>

我无法将数量与相应的价格相乘，然后得到总和。我在这里做错了什么？

4

1 回答 1

2

创建元素时，会评估大括号内的所有内容（并且不会评估大括号外的任何内容）。由于您只在变量周围放置了大括号，因此只有这些被替换，但不执行乘法。

替换为这一行：

{ $k/qty * $p[@pno=$k/pNum]/price }
于 2013-04-24T12:12:08.773 回答