Cannot perform an aggregate function on an expression containing an aggregate or a subquery.

I am getting "Cannot perform an aggregate function on an expression containing an aggregate or a subquery." error by executing below query, I need to calculate the percentage. Can you please help me on this by modifying the query.



select oe2.OrdSourceID,Count(oe2.OrdSourceID) as TotalOrders,
Percentage = Count(oe2.OrdSourceID) * 100.0 / SUM(Count(oe2.OrdSourceID))
  from OeOrders Oe 
  iNNER JOIN OeOrders2 AS oe2
       ON Oe.OrderID = oe2.OrderID
where
Oe.ProviderID = 'JOHN' and Oe.OrderDateTime between '10/07/2014' and '10/15/2014' and oe2.OrdSourceID is not null
  AND Oe.[Status] NOT IN ( 'CANCEL', 'CANC', 'CNC', 'UNVER', 'UNV' )
Group by oe2.OrdSourceID



Thanks..

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Diddi