XQuery中的排序插入

Question

我想每一輛通過的總價值atrribute以降序排序後，

數據排序後，我想添加屬性級別節點租車。

但是當我運行我的代碼結果不是按降序排列。

我的XML文件：

<Cars> 
<Car TotalValue="27000"> 
<CarDetail Name="Peugot-206"/> 
</Car> 

<Car TotalValue="28000"> 
<CarDetail Name="Peugot-206"/> 
</Car> 

<Car TotalValue="30000"> 
<CarDetail Name="Peugot-206"/> 
</Car> 

<Car TotalValue="35000"> 
<CarDetail Name="Peugot-206"/> 
</Car> 

<Car TotalValue="270000"> 
<CarDetail Name="Peugot-206"/> 
</Car> 

<Car TotalValue="280000"> 
<CarDetail Name="Peugot-206"/> 
</Car> 

<Car TotalValue="300500"> 
<CarDetail Name="Peugot-206"/> 
</Car> 

<Car TotalValue="40000"> 
<CarDetail Name="Peugot-206"/> 
</Car> 

<Car TotalValue="270000"> 
<CarDetail Name="Peugot-206"/> 
</Car> 

<Car TotalValue="280000"> 
<CarDetail Name="Peugot-206"/> 
</Car> 

<Car TotalValue="3005000"> 
<CarDetail Name="Peugot-206"/> 
</Car> 

<Car TotalValue="400000"> 
<CarDetail Name="Peugot-206"/> 
</Car> 
</Cars> 

我的代碼：

let $sortResult := for $Car in doc('Process')//Car 
       let $value:=number($Car/@TotalValue) 
       order by $value descending 
       return $Car 
for $sortItem at $position in $sortResult 
return insert node (attribute Level {$position}) 
into $sortItem 

運行結果：

<Cars> 
<Car Level="12" TotalValue="27000"> 
<CarDetail Name="Peugot-206"/> 
</Car> 

<Car Level="11" TotalValue="28000"> 
<CarDetail Name="Peugot-206"/> 
</Car> 

<Car Level="10" TotalValue="30000"> 
<CarDetail Name="Peugot-206"/> 
</Car> 

<Car Level="9" TotalValue="35000"> 
<CarDetail Name="Peugot-206"/> 
</Car> 

<Car Level="6" TotalValue="270000"> 
    <CarDetail Name="Peugot-206"/> 
</Car> 

<Car Level="4" TotalValue="280000"> 
<CarDetail Name="Peugot-206"/> 
</Car> 

<Car Level="3" TotalValue="300500"> 
<CarDetail Name="Peugot-206"/> 
</Car> 

<Car Level="8" TotalValue="40000"> 
<CarDetail Name="Peugot-206"/> 
</Car> 

<Car Level="7" TotalValue="270000"> 
    <CarDetail Name="Peugot-206"/> 
</Car> 

<Car Level="5" TotalValue="280000"> 
    <CarDetail Name="Peugot-206"/> 
</Car> 

<Car Level="1" TotalValue="3005000"> 
    <CarDetail Name="Peugot-206"/> 
</Car> 

<Car Level="2" TotalValue="400000"> 
<CarDetail Name="Peugot-206"/> 
</Car> 

</Cars> 

我需要：

<Cars> 
<Car Level="1" TotalValue="3005000"> 
<CarDetail Name="Peugot-206"/> 
</Car> 

<Car Level="2" TotalValue="400000"> 
<CarDetail Name="Peugot-206"/> 
</Car> 

<Car Level="3" TotalValue="300500"> 
<CarDetail Name="Peugot-206"/> 
</Car> 

<Car Level="4" TotalValue="280000"> 
<CarDetail Name="Peugot-206"/> 
</Car> 

<Car Level="5" TotalValue="280000"> 
<CarDetail Name="Peugot-206"/> 
</Car> 

<Car Level="6" TotalValue="270000"> 
<CarDetail Name="Peugot-206"/> 
</Car> 

<Car Level="7" TotalValue="270000"> 
    <CarDetail Name="Peugot-206"/> 
</Car> 

<Car Level="8" TotalValue="40000"> 
    <CarDetail Name="Peugot-206"/> 
</Car> 

<Car Level="9" TotalValue="35000"> 
    <CarDetail Name="Peugot-206"/> 
</Car> 

<Car Level="10" TotalValue="30000"> 
    <CarDetail Name="Peugot-206"/> 
</Car> 

<Car Level="11" TotalValue="28000"> 
    <CarDetail Name="Peugot-206"/> 
</Car> 

<Car Level="12" TotalValue="27000"> 
    <CarDetail Name="Peugot-206"/> 
</Car> 
</Cars> 

Answer 1

你使用XQuery更新修改原始數據。你的查詢實際上不應該返回任何東西。

無論使用XQuery更新的copy語句（您可以在以後修改），或者簡單地重新創建<Car/>節點：

for $car at $position in (
    for $car in $xml//Car 
    let $value := number($car/@TotalValue) 
    order by $value descending 
    return $car 
) 
return element Car { 
    attribute Level { $position }, 
    $car/attribute(), 
    $car/node() 
}