title: List Of List group Result
body: <p>I have a list of list as follows</p>
  
  <pre><code>    var left = (from T in brndT
          join S in brndS
          on T.ID equals S.ID
          into temp
          from S in temp.DefaultIfEmpty()
          select new BrandSalesTarget
          {
               ID = T.ID,
               Target = T.Target == null ? 0 : (int)T.Target,
               Sales = S != null ? (int)S.Qty : 0
          }).ToList();
     listOfList.Add(left);
  </code></pre>
  
  <p>Now I want <code>ID, TotalTarget, TotalSales</code> 
  which means group by list of list with <code>ID, Sum(target), Sum(sales)</code>. How to do it?</p>