MySQL查詢。給最接近的日期至當前

Question

我有這個查詢，讓我回來多個結果。我想編輯它，這樣它只會給我一個結果，每個o.Customer_ID，然後這就是今天最接近o.OrderPlaceServerTime的訂單。

這裏的查詢我：

SELECT 
    o.Order_ID, 
    o.Customer_ID, 
    o.OrderPlaceServerTime, 
    o.CustomerOrderTotal 
FROM 
    Orders o 
    LEFT JOIN Order_LineDetails oln 
    ON oln.Order_ID = o.Order_ID 
WHERE 
    o.OrderPlaceServerTime >= '2012-09-01 00:00:00' 
AND o.OrderPlaceServerTime <= '2012-12-01 00:00:00' 
AND o.CustomerOrderTotal >= '50' 
AND oln.Product_ID = '75' 

什麼會，我需要改變，以實現這一目標？

Answer 1

我想編輯它，這樣它纔會給我一個結果每o.Customer_ID

所以，首先你應該得到的符合條件的客戶ID的最新訂單，通過分組預選賽按客戶ID訂購併選擇最大或OrderPlaceServerTime。然後，您會將這些記錄與訂單上的客戶ID和OrderPlaceServerTime結合起來，以選擇其他兩個感興趣的屬性。

SELECT 
    o.Order_ID, 
    o.Customer_ID, 
    o.OrderPlaceServerTime, 
    o.CustomerOrderTotal 
FROM 
    Orders o 
    JOIN (
     SELECT 
      o.Customer_ID, 
      MAX(o.OrderPlaceServiceTime) 'MaxOrderPlaceServiceTime' 
     FROM 
      Orders o 
      LEFT JOIN Order_LineDetails oln 
      ON oln.Order_ID = o.Order_ID 
     WHERE 
      o.OrderPlaceServerTime >= '2012-09-01 00:00:00' 
     AND o.OrderPlaceServerTime <= '2012-12-01 00:00:00' 
     AND o.CustomerOrderTotal >= '50' 
     AND oln.Product_ID = '75' 
     GROUP BY o.Customer_ID 
    ) AS A 
    ON 
     o.Customer_ID = A.Customer_ID AND 
     o.OrderPlaceServiceTime = A.MaxOrderPlaceServiceTime 

Answer 2

如果我理解正確的，你需要的東西，這應該是查詢：

SELECT * FROM 

    (SELECT 
    o.Order_ID, 
    o.Customer_ID, 
    o.OrderPlaceServerTime, 
    o.CustomerOrderTotal 
    FROM 
     Orders o 
     LEFT JOIN Order_LineDetails oln 
     ON oln.Order_ID = o.Order_ID 
    WHERE 
     o.OrderPlaceServerTime >= '2012-09-01 00:00:00' 
    AND o.OrderPlaceServerTime <= '2012-12-01 00:00:00' 
    AND o.CustomerOrderTotal >= '50' 
    AND oln.Product_ID = '75'  
    ORDER BY o.Customer_ID, o.OrderPlaceServerTime DESC) AS tab1 

    GROUP BY o.Customer_ID;