It could happen that some objects do not have a value for a particular reporting column - for example if the report contain a 'duration' column, this will have a value for audio and video objects but not for images.

In such cases the XSLT should either completely omit the value from the output or mark the valus as 'null' using the xsi:nil attribute - e.g. assuming to have added the 'duration' column, the output for an image should be:

    . . .

    <r>

      <id>6826</id>

      <type>image</type>

      <size>38966</size>

    </r>

    . . .

or

    . . .

    <r xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

      <id>6826</id>

      <type>image</type>

      <size>38966</size>

      <duration xsi:nil="true"/>

    </r>

    . . .