使用 XPath 1.0 仅选择不同的值

Selecting only distinct values using XPath 1.0

我如何 return 只有 unique CityName state = 'Washington' 使用 XPath 1.0?

<StateDataSet>
    <State>
        <Name>Washington</Name>
        <City>Seattle</City>
        <business>Starbucks</business>
    </State>
    <State>
        <Name>Washington</Name>
        <City>Seattle</City>
        <business>Amazon</business>
    </State>
    <State>
        <Name>Washington</Name>
        <City>Redmond</City>
        <business>Microsoft</business>
    </State>
    <State>
        <Name>Washington</Name>
        <City>Redmond</City>
        <business>Starbucks</business>
    </State>
    <State>
        <Name>Washington</Name>
        <City>Seattle</City>
        <business>Dicks</business>
    </State>
    <State>
        <Name>Alaska</Name>
        <City>Anchorage</City>
        <business>Starbucks</business>
    </State>
    <State>
        <Name>Oregon</Name>
        <City>Portland</City>
        <business>Starbucks</business>
    </State>
    <State>
        <Name>Alaska</Name>
        <City>Gnome</City>
        <business>Starbucks</business>
    </State>
</StateDataSet>

到目前为止,我已经尝试了以下 XPath 查询:

/StateDataSet/State[Name ='Washington' and not (State[Name='Washington'] = following-sibling::State[Name='Washington'])]/City

这 return 编辑了华盛顿的城市,但值不是唯一的。我使用 xpathtester.com

测试了我的查询

我做错了什么?我的查询基于 get-distinct-values-within-specific-attributes

这个 XPath,

/StateDataSet/State[Name ='Washington' and 
                    not(City = preceding-sibling::State[Name='Washington']/City)]
             /City

将 select State 元素中唯一的 City 元素 Name = 'Washington':

<City>Seattle</City>
<City>Redmond</City>

根据要求。