sum some xml nodes values in sql server 2008

Question

Please consider this XML:

    10 
    20 
    

        

Answer 1

Try this :-

 Declare @xml xml 
set @xml='
         10 
         20 
         0 
          '

 Select @xml.value('sum(/Parent/Child)','int') as Sum

Result : 30

or if you want the sum for a specific Parent ID then try the below query

 Select @xml.value('sum(/Parent/Child)','int') AS SumVal
 where @xml.exist('/Parent[@ID="p"]') = 1;

Demo in SQL FIDDLE