You simply need to name your subquery:SELECT ITEMNO, WHOUSE, Sum(QTY) AS SUMQTYFROM((SELECT t.item_id AS ITEMNO, dbo.inventory_receipts_d.warehouse_no AS WHOUSE, ISNULL(dbo.inventory_receipts_d.received_quantity,0)AS QTYFROM dbo.inventory_receipts_dJOIN dbo.items t ON dbo.inventory_receipts_d.item_id= t.item_idWHERE t.primary_item_category_no='INVEN' AND t.record_status='A')UNION(SELECT u.item_id, dbo.inventory_activity_transfer_d.warehouse_no, (CASEWHEN dbo.inventory_activity_transfer_d.transfer_type = 'F'AND dbo.inventory_activity_transfer_d.move_from_to='W'AND dbo.inventory_activity_d.item_id = u.item_idTHEN (-1)*isnull(dbo.inventory_activity_transfer_d.stocking_quantity,0)WHEN dbo.inventory_activity_transfer_d.transfer_type = 'T'AND dbo.inventory_activity_transfer_d.move_from_to='W'AND dbo.inventory_activity_d.item_id = u.item_idTHEN (1)*isnull(dbo.inventory_activity_transfer_d.stocking_quantity,0)ELSE 0END) AS QTYFROM dbo.items uJOIN dbo.inventory_activity_d ON u.item_id = dbo.inventory_activity_d.item_idJOIN dbo.inventory_activity_transfer_d ON dbo.inventory_activity_d.transaction_no = dbo.inventory_activity_transfer_d.transaction_noAND dbo.inventory_activity_d.line_no = dbo.inventory_activity_transfer_d.line_noWHERE u.primary_item_category_no='INVEN' AND u.record_status='A')) AGROUP BY ITEMNO, WHOUSEORDER BY ITEMNO
Some days you're the dog, and some days you're the fire hydrant.