SQL Server : FOR XML PATH - nesting / grouping

Question

I have data that looks like:

OrderID CustomerID  ItemID  ItemName
10000   1234        111111  Product A
10000   1234        222222  Product B
10000   1234            


        

Answer 1

select  
    OrderID,
    CustomerID,
    (
        select 
        ItemID,
        ItemName
        from @Orders rsLineItem
        where rsLineItem.OrderID = rsOrders.OrderID
        for xml path('LineItem'), type
    )
from (select distinct OrderID, CustomerID from @Orders) rsOrders
FOR XML PATH ('Order'), root ('Root')