>>>>Now I get
>>>>

>>>>Msg 8156, Level 16, State 1, Procedure ap_GetReturnsForWarehouse, Line 23
>>>>The column 'Status' was specified multiple times for 'OrderedResultS'.
>>>>Msg 4104, Level 16, State 1, Procedure ap_GetReturnsForWarehouse, Line 23
>>>>The multi-part identifier "OrderedResultSet.RowNum" could not be bound.
>>>>Msg 4104, Level 16, State 1, Procedure ap_GetReturnsForWarehouse, Line 23
>>>>The multi-part identifier "p.PartNo" could not be bound.
>>>>Msg 4104, Level 16, State 1, Procedure ap_GetReturnsForWarehouse, Line 23
>>>>The multi-part identifier "r.SerialNo" could not be bound.
>>>>

>>>>
>>>>There are elements in that query I have never seen before. Very confusing.
>>>
>>>The inner part ( with row_number() ) was supposed to be a derived table. I'm guessing you didn't use
>>>
>>>select * from (derived table select with row_number()) OrderedRecordSet (alias I gave to the derived table) where rowNum = 1
>>>
>>>Can you post your exact query now to correct ?
>>
>>I used exactly what you posted earlier:
>>
>>

>>select * from (SELECT	r.*, 
>>			p.PartNo, 
>>			p.Description,
>>			u.FullName,
>>			w.Caption AS Warehouse,
>>			r.Status, Row_Number() OVER (Partition by BatchID ORDER BY p.PartNo, r.SerialNo DESC) as RowNum
>>		FROM Returns r
>>		JOIN Parts p ON p.PartId = r.PartId
>>		JOIN Warehouses w ON w.WarehouseId = r.WarehouseId
>>		JOIN Users u ON u.UserId = r.UserId
>>		WHERE r.WarehouseId = @WarehouseId AND
>>			(@Status IS NULL or r.Status = @Status)) OrderedResultS 
>>            where OrderedResultSet.RowNum = 1
>>		ORDER BY BatchId, p.PartNo, r.SerialNo DESC
>>

>
>oops - remove aliases in the last line ORDER BY
>
> ORDER BY BatchId - we don't even need more orders - since we get only one record per batch
>

>>select * from (SELECT	r.*, 
>>			p.PartNo, 
>>			p.Description,
>>			u.FullName,
>>			w.Caption AS Warehouse,
>>			r.Status, Row_Number() OVER (Partition by BatchID ORDER BY p.PartNo, r.SerialNo DESC) as RowNum
>>		FROM Returns r
>>		JOIN Parts p ON p.PartId = r.PartId
>>		JOIN Warehouses w ON w.WarehouseId = r.WarehouseId
>>		JOIN Users u ON u.UserId = r.UserId
>>		WHERE r.WarehouseId = @WarehouseId AND
>>			(@Status IS NULL or r.Status = @Status)) OrderedResultS 
>>            where OrderedResultS.RowNum = 1
>>		ORDER BY BatchId

Still getting

Msg 8156, Level 16, State 1, Procedure ap_GetReturnsForWarehouse, Line 23
The column 'Status' was specified multiple times for 'OrderedResultS'.
Msg 4104, Level 16, State 1, Procedure ap_GetReturnsForWarehouse, Line 23
The multi-part identifier "OrderedResultSet.RowNum" could not be bound.