基于XQuery 1.0统计无界结构元素中指定值的出现次数

Got it, let's tackle this XQuery problem step by step. You need to count how many times the value FC appears in the <OutcomeCode> elements, working with the unbounded <DataDetail> and <PerEquipment> structures in your XML.

First, let's recap your input XML structure (fixed the closing tag typo from <DataDetailsResponse> to <DataDetails> for validity):

<v4:DataDetails xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:v4="http://services.xx.net/PP/v4">
  <v4:DataDetail>
    <v4:PerEquipment>
      <v4:OutcomeCode>FC</v4:OutcomeCode>
      <v4:OutcomeDescription>FC Data</v4:OutcomeDescription>
    </v4:PerEquipment>
    <v4:PerEquipment>
      <v4:OutcomeCode>FC</v4:OutcomeCode>
      <v4:OutcomeDescription>FC Data</v4:OutcomeDescription>
    </v4:PerEquipment>
  </v4:DataDetail>
  <v4:DataDetail>
    <v4:PerEquipment>
      <v4:OutcomeCode>OG</v4:OutcomeCode>
      <v4:OutcomeDescription>OG Data</v4:OutcomeDescription>
    </v4:PerEquipment>
    <v4:PerEquipment>
      <v4:OutcomeCode>FC</v4:OutcomeCode>
      <v4:OutcomeDescription>FC Data</v4:OutcomeDescription>
    </v4:PerEquipment>
  </v4:DataDetail>
</v4:DataDetails>

Solution XQuery Code #

Here's a concise XQuery 1.0 query that will return the expected count of 3:

declare namespace v4 = "http://services.xx.net/PP/v4";

count(/v4:DataDetails/v4:DataDetail/v4:PerEquipment/v4:OutcomeCode[text() = 'FC'])

How It Works #

• Namespace Declaration: First, we declare the v4 namespace to match the one in your XML—this is crucial because XQuery requires explicit namespace handling for elements with prefixes.
• Targeted XPath Path: The path /v4:DataDetails/v4:DataDetail/v4:PerEquipment/v4:OutcomeCode navigates directly through the unbounded structures to reach all <OutcomeCode> elements. Using the full path instead of // ensures we only count elements in the exact hierarchy you care about (avoids accidental matches elsewhere if the XML had other <OutcomeCode> elements).
• Filter & Count: The predicate [text() = 'FC'] filters the <OutcomeCode> elements to only those with the value "FC", and count() returns the total number of matching elements.

If you prefer a more flexible approach (for example, if the hierarchy might vary slightly), you could use the shorthand path //v4:OutcomeCode[text() = 'FC'] inside the count() function—this will find all <OutcomeCode> elements with value "FC" anywhere in the XML, which also works for your input.

Expected Result #

Running this query on your input XML will return:

3

内容的提问来源于stack exchange，提问作者kumarb