在union - group中共享行？

Question

我有這樣的查詢：

SELECT * FROM (
    SELECT id, SUM(orderLineTotal) as orderLine1, NULL as orderLine 2 
    FROM Orders 
    WHERE Orders.Date < @Today 
    GROUP BY id 

    UNION 

    SELECT id, NULL as orderLine1, SUM(orderLineTotal2) as orderLine 2 
    FROM Orders 
    WHERE Orders.Date = @Today 
    GROUP BY id 
) o 
GROUP BY o.id, o.orderLine1, o.orderLine2 

我得到類似下面的結果：

ID   OrderLine1   OrderLine2 
----------------------------------------- 
1   105.00    NULL 
1   NULL    204.00 
2   49.30    NULL 
2   NULL    94.24 

有什麼辦法來修改查詢返回這樣的事情？

ID   OrderLine1   OrderLine2 
----------------------------------------- 
1   105.00    204.00 
2   49.30    94.24 

Answer 1

你想使用一個查詢和條件聚集做到這一點：

SELECT id, 
      SUM(case when Orders.Date < @Today then orderLineTotal end) as orderLine1, 
      SUM(case when Orders.Date = @Today then orderLineTotal2 end) as orderLine2 
    FROM Orders 
    GROUP BY id 

順便說一句，是真的有兩列，orderLineTotal和orderLineTotal2？我懷疑只有一個，第二個sum()應該相應地改變。