从XML SQL Select语句获取值

Question

我正在尝试理解和学习如何从XML中获取价值。我从下面的链接中获取了XML文档的参考。

Link

为了澄清，我删除了一些不需要的xml部分。

示例

<?Label VCAT|RESERVATION|21405|SUCCESS?> 
<Reservation xmlns="reservation.fidelio.4.0" mfShareAction="NA" mfReservationAction="EDIT">
    <HotelReference>
        <GuestCounts>
            <GuestCount>
                <ageQualifyingCode>ADULT</ageQualifyingCode> 
                <mfCount>1</mfCount> 
            </GuestCount>
            <GuestCount>
                <ageQualifyingCode>CHILD</ageQualifyingCode> 
                <mfCount>0</mfCount> 
            </GuestCount>
        </GuestCounts>
    </HotelReference>
</Reservation>

[在HTML中，例如google.com-为了将该页面的输入作为目标，我们使用XPath作为//input[@name='q']。同样，为了定位一个节点，我们可以指定//ageQualifyingCode以在该节点内获取值。因此，基于此，我创建了下面指定的查询。谁能告诉我此查询出了什么问题，因为我将输出为NULL。

DECLARE @XmlDocumentHandle int 
DECLARE @XMLData XML
SET @XMLData ='<?Label VCAT|RESERVATION|21405|SUCCESS?> 
<Reservation xmlns="reservation.fidelio.4.0" mfShareAction="NA" mfReservationAction="EDIT">
    <HotelReference>
        <GuestCounts>
            <GuestCount>
                <ageQualifyingCode>ADULT</ageQualifyingCode> 
                <mfCount>1</mfCount> 
            </GuestCount>
            <GuestCount>
                <ageQualifyingCode>CHILD</ageQualifyingCode> 
                <mfCount>0</mfCount> 
            </GuestCount>
        </GuestCounts>
    </HotelReference>
</Reservation>'
EXEC sp_xml_preparedocument @XmlDocumentHandle OUTPUT, @XMLData  

SELECT *  
FROM OPENXML (@XmlDocumentHandle, '/Reservation/HotelReference/GuestCounts/GuestCount/',2)  
WITH (ageQualifyingCode     varchar(10)   '//ageQualifyingCode',  
      mfCount  int '//mfCount')  
EXEC sp_xml_removedocument @XmlDocumentHandle

Answer 1

尝试使用XQuery方法-定义XML名称空间，然后查询XML：

DECLARE @XMLData XML
SET @XMLData ='<?Label VCAT|RESERVATION|21405|SUCCESS?> 
<Reservation xmlns="reservation.fidelio.4.0" mfShareAction="NA" mfReservationAction="EDIT">
    <HotelReference>
        <GuestCounts>
            <GuestCount>
                <ageQualifyingCode>ADULT</ageQualifyingCode> 
                <mfCount>1</mfCount> 
            </GuestCount>
            <GuestCount>
                <ageQualifyingCode>CHILD</ageQualifyingCode> 
                <mfCount>0</mfCount> 
            </GuestCount>
        </GuestCounts>
    </HotelReference>
</Reservation>';

WITH XMLNAMESPACES(DEFAULT 'reservation.fidelio.4.0')
SELECT
    xc.value('(ageQualifyingCode)[1]', 'varchar(20)'),
    xc.value('(mfCount)[1]', 'int')
FROM
    @XMLData.nodes('/Reservation/HotelReference/GuestCounts/GuestCount') AS XT(XC)

这将返回两行，分别为<ageQualifyingCode>和<mfCount>的值：