Removing duplicates in xml with xslt

Question

I need to remove duplicates in the following xml:

Answer 1

If you interested in how this is achieved using Muenchian Grouping, which is a common technique in XSLT, you first need to define a 'key' to identify duplicate books within a row.

In this I am achieving this using a concatenated key of RowID, BookType and BookName. The key will contain a list of books all with that particular value of key. Do note the use of the # character as the joining character. If there is any chance of # appearing in your XML, you will need to pick another character (or string).

Now when you are matching on book elements, you can check for duplicates like so

In other words, is this book element the first element in our key.

Here is the full XSLT

Also note the use of the identity transform so that other nodes can be copied without having to explicitly reference them. When this XSLT is applied to your input, the following output is generated:

   ADOA-XssK
   
      
         Brand
         jon
      
   

EDIT: I have amended the XSLT to remove an unnecessary template match.