XSLT: Sorting based on sum of values from other nodes

Question

I\'m rather new to coding xslt and have got rather stuck trying to do the following.

I have an xml file that has breeding info for horses broken into two main sectio

Answer 1

This transformation:

 
 

 
  
   
  
 

 
     Sire 
   
 
 

when applied on the provided XML document:

    
        
            1
            hrsA
            101
            
                4800
            
        
        
            2
            hrsB
            102
            
                3600
            
        
        
            3
            hrsC
            102
            
                2800
            
        
        
            4
            hrsD
            101
            
                56
            
        
        
            5
            hrsE
            100
            
                20000
            
        
        
            6
            hrsF
            101
            
                20000
            
        
        
            7
            hrsG
            101
            
                559
            
        
        
            8
            hrsH
            102
            
                386
            
            
                10000
            
        
    
    
        
            100
            srA
            117
        
        
            101
            srB
            774
        
        
            102
            srC
            43
        
    

produces the wanted, correct result:

 Sire 101 (srB) Stakes: 25415
 Sire 100 (srA) Stakes: 20000
 Sire 102 (srC) Stakes: 16786

Explanation:

1. We define a key that specifies a Horse as a function of its SireID. This is useful in selecting all offspring of a given Sire just by providing its ID in a call to the standard XSLT key() function -- like this: key('kOffspring', ID).

2. Similarly, the sum of Stakes of all offspring of a given Sire is: sum(key('kOffspring', ID)/*/Stakes) .

3. We apply templates to all Sire elements in the XML document and sort these by the decreasing values of the sums of the Stakes of their offsprings.

4. For each Sire we output its ID, Name and the sum of Stakes of its offspring.