XPath to select parent where children meet certain criteria

xpath_selection.md

For the code below, if we want to select records have a field with colour = Red and length > 30...

<root>
<record id="1">
  <field id="colour" value="Red" />
  <field id="size"   value="Small" />
  <field id="length" value=25 />
</record>
<record id="2">
  <field id="colour" value="Red" />
  <field id="size"   value="Large" />
  <field id="length" value=50 />
</record>
</root>

Then we case use the following XPath1.0:

record[field[@id='colour' and @value='Red'] and field[@id='length' and @value > 30]]