[xsl] Multi condition sum [Correction]

["peter verhaar" <peter.verhaar1@xxxxxxxxx>]

Hello,

Sorry my last message was send to early.

I have one question. assume this snippet:

<books>
 <book>
   <column name="quantity">50</column>
   <column name="status">available</column>
 </book>
 <book>
   <column name="quantity">10</column>
   <column name="status">available</column>
 </book>
 <book>
   <column name="quantity">3</column>
   <column name="status">lost</column>
 </book>
</books>


Now I want to add all Quantity IF Status = "Available".

All sum is this: sum(books/book[@name="quantity"])

but how to add the Status = "Available" condition???

Thank you