for xml path(''),root('')

select  stuff(RTRIM(Convert(varchar(max),(SELECT distinct ','+sku FROM AmazonSellingList where AmazonStatus!='Deleted'  FOR XML PATH('')))),1,1,'')

SELECT top 10 
ROW_NUMBER()OVER(ORDER BY OperationID) as 'Message/MessageId',
OperationID  as  'ItemData/OperationID', 
Code as  'ItemData/Code',
ID as  'ItemData/ID'
from TableName 
FOR XML PATH('Message')