CODEWITHSUNDEEP
xmlvariablesxquery
missdevops
missdevops

Reputation: 359

Simple XQuery on XML feed - help on defining a variable

I have never done XQuery before and I need to write a statement using a variable instead of hard-coding in values as this is a live XML feed. (Sorry for such a basic question)

Each event has a name, and a number of places taken, and a number of empty places that are available. Instead of hard-coding in 4 and 11, I want to make these a variable which is that of a specific event.

The event is /event/name = "Rock concert" and I want 

nb_places = that of "Rock Concert" and nb_empty_places >= that of "Rock Concert"

This is what I have so far:

<bib>
{
  for $n in doc("http://tinyurl.com/")/event
  where $n/nb_places = 4 and $n/nb_empty_places >= 11
  return
    <result>
     { $n/nb_empty_places }
     { $n/nb_places }
     { $n/name }
    </result>
  }
</bib>

Thank you :)

Example XML:

<event>
<name>Rock Concert</name>
<nb_places>4</nb_places>
<nb_empty_places>11</nb_empty_places>
</event>
<event>
<name>Indie Concert</name>
<nb_places>4</nb_places>
<nb_empty_places>9</nb_empty_places>
</event>
<event>
<name>RnB Concert</name>
<nb_places>2</nb_places>
<nb_empty_places>14</nb_empty_places>
</event>
<event>
<name>Pop Concert</name>
<nb_places>3</nb_places>
<nb_empty_places>32</nb_empty_places>
</event>
<event>
<name>House Concert</name>
<nb_places>4</nb_places>
<nb_empty_places>20</nb_empty_places>
</event>

Desired result, events with the same number places as Rock Concert, and the same or more number of empty places:

<result>
    <nb_empty_places>32</nb_empty_places>
    <nb_places>4</nb_places>
    <name>Rock Concert</name>
  </result>
  <result>
      <nb_empty_places>20</nb_empty_places>
      <nb_places>4</nb_places>
      <name>House Concert</name>
    </result>

Upvotes: 1

Views: 33

Answers (1)

har07
har07

Reputation: 89285

This is one possible way :

declare variable $nb_places := root/event[name='Rock Concert']/nb_places;
declare variable $nb_empty_places := root/event[name='Rock Concert']/nb_empty_places;
<bib>
{
  for $n in root/event
  where $n/nb_places = $nb_places and $n/nb_empty_places/number() >= $nb_empty_places
  return
    <result>
     { $n/nb_empty_places }
     { $n/nb_places }
     { $n/name }
    </result>
  }
</bib>

Demo : xpathtester

Upvotes: 1

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