web-server/data/release/demo/WFS_mathGetFeature.xml

<!-- Example of a getFeature with a math filter.  In this case  -->
<!-- we want the states that have over 25% of their workers -->
<!-- doing manual labor.  So we divide the manual field by    -->
<!-- the total number of workers and compare it against 0.25 -->

<wfs:GetFeature service="WFS" version="1.0.0"
  outputFormat="GML2"
  xmlns:topp="http://www.openplans.org/topp"
  xmlns:wfs="http://www.opengis.net/wfs"
  xmlns:ogc="http://www.opengis.net/ogc"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.opengis.net/wfs
                      http://schemas.opengis.net/wfs/1.0.0/WFS-basic.xsd">
  <wfs:Query typeName="topp:states">
    <ogc:Filter>
      <ogc:PropertyIsGreaterThan>
        <ogc:Div>
            <ogc:PropertyName>MANUAL</ogc:PropertyName>
            <ogc:PropertyName>WORKERS</ogc:PropertyName>
        </ogc:Div>
         <ogc:Literal>0.25</ogc:Literal>
    </ogc:PropertyIsGreaterThan>
    </ogc:Filter>
    </wfs:Query>
</wfs:GetFeature>