xpath - 在XQuery中查找有关最新元素的信息

Question

我有一个这样的xml文件：

 <carSchema xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="carSchema.xsd">
 <car>
    <License>23</License>
    <year>2010</year>
    <model>a</model>
    <manufacturer>hyundai</manufacturer>
</car>
<car>
    <License>24</License>
    <year>2002</year>
    <model>b</model>
    <manufacturer>hyundai</manufacturer>
</car>
<car>
    <License>25</License>
    <year>2005</year>
    <model>c</model>
    <manufacturer>hyundai</manufacturer>
</car>
<car>
    <License>26</License>
    <year>2004</year>
    <model>d</model>
</car>
<car>
    <License>27</License>
    <year>2016</year>
    <model>f</model>
    <manufacturer>hyundai</manufacturer>
</car>

我想在Xquery中找到有关最新汽车的信息。我写了这个查询最新汽车的返回年份。

 xquery version "1.0";
 max(
 for $x in doc("car.xml")/carSchema/car
   order by $x/year descending
 return $x/year)

如何返回有关该车的所有信息（许可证，型号，制造商）？

Answer 1

您可以使用

(for $car in doc("car.xml")/carSchema/car
order by $car/year descending
return $car)[1]/*

查找具有最近年份的元素的所有子元素，或

(for $car in doc("car.xml")/carSchema/car
order by $car/year descending
return $car)[1]

查找最近一年的元素本身。