a.xml

<?xml version="1.0" encoding="UTF-8"?>
<table xmlns="http://query.yahooapis.com/v1/schema/table.xsd">
  <meta>
    <sampleQuery>select * from {table} where a='cat' and b='dog';</sampleQuery>
  </meta>
  <bindings>
    <select itemPath="zoo" produces="XML">
      <urls>
        <url>http://fake.url/{a}</url>
      </urls>
      <inputs>
        <key id='a' type='xs:string' paramType='path' required="true" />
        <key id='b' type='xs:string' paramType='variable' required="true" />
      </inputs>
      <execute><![CDATA[
          // Your javascript goes here. We will run it on our servers
          response.object = <item>
                   <url>{request.url}</url>
                   <a>{a}</a>
                   <b>{b}</b>
                </item>;
      ]]></execute>
    </select>
  </bindings>
</table>