如何计算和组合两个查询

Question

我正在使用此查询进行组合和计数。有时它有效，有时它不起作用。个别查询有时彼此不相等。这里有什么问题吗？有没有更好/更简单的方法来做到这一点？提前谢谢。

SELECT   CONVERT(VarChar(8), End_Date, 112)as End_Date,count(*) as Qty, 'LPFG' as     Wc_Code 
FROM
(
 (SELECT  dimdbmc.dbo.t_Allocation_Event.Demand_Order_Nbr, Demand_Order_Line_Nbr,
CONVERT(VARCHAR(8), min(dimdbmc.dbo.t_Allocation_Event.Row_Insert_Datetime), 112) as     End_Date
FROM dimdbmc.dbo.t_Allocation_Event INNER JOIN dimdbmc.dbo.t_Demand_Order ON    (dimdbmc.dbo.t_Allocation_Event.MMM_Facility_Code = dimdbmc.dbo.t_Demand_Order.MMM_Facility_Code) AND (dimdbmc.dbo.t_Allocation_Event.Demand_Order_Nbr = dimdbmc.dbo.t_Demand_Order.Demand_Order_Nbr)
WHERE (((dimdbmc.dbo.t_Allocation_Event.MMM_Facility_Code)='MC') 
AND ((dimdbmc.dbo.t_Allocation_Event.Event_Type_Code)='Allocate') 
AND dimdbmc.dbo.t_demand_order.demand_order_type_code IN  ( 'COMS-SMPNO') 
AND ((dimdbmc.dbo.t_Allocation_Event.Row_Insert_Datetime)>= '8/01/2012'))
Group by
dimdbmc.dbo.t_Allocation_Event.Demand_Order_Nbr,    dimdbmc.dbo.t_Allocation_Event.Demand_Order_Line_Nbr)
 UNION ALL

(SELECT  dimdbmc.dbo.t_Allocation_Event.Demand_Order_Nbr, Demand_Order_Line_Nbr,
CONVERT(VARCHAR(8), min(dimdbmc.dbo.t_Allocation_Event.Row_Insert_Datetime), 112) as    End_Date
FROM dimdbmc.dbo.t_Allocation_Event INNER JOIN dimdbmc.dbo.t_Demand_Order ON    (dimdbmc.dbo.t_Allocation_Event.MMM_Facility_Code = dimdbmc.dbo.t_Demand_Order.MMM_Facility_Code) AND (dimdbmc.dbo.t_Allocation_Event.Demand_Order_Nbr = dimdbmc.dbo.t_Demand_Order.Demand_Order_Nbr)
WHERE (((dimdbmc.dbo.t_Allocation_Event.MMM_Facility_Code)='MC') 
AND ((dimdbmc.dbo.t_Allocation_Event.Demand_Order_Nbr) Is Not Null) 
AND ((dimdbmc.dbo.t_Allocation_Event.Event_Type_Code)='Allocate') 
AND substring(dimdbmc.dbo.t_Demand_Order.Demand_Order_Nbr, 8, 1) <>'_'  
AND dimdbmc.dbo.t_demand_order.demand_order_type_code IN  ( 'COMS-CUST','COMS-   GOVT','COMS-INTL') 
AND ((dimdbmc.dbo.t_Demand_Order.Charge_To_Customer_Nbr)='WHP4101')
AND ((dimdbmc.dbo.t_Allocation_Event.Row_Insert_Datetime)>= '8/01/2012'))
Group by
dimdbmc.dbo.t_Allocation_Event.Demand_Order_Nbr,dimdbmc.dbo.t_Allocation_Event.Demand_Order_Line_Nbr
)

)as a

 group by End_Date
order by End_Date