我會運行什麼SQL查詢來獲取我失去的拍賣清單？ （eBay示例）

Question

我會嘗試給出一個「eBay」示例，我相信這將是最簡單的方法。

想象的bids表：

bid_id | bid_from_user | bid_for_auction | bid_price 
1  | 150   | 1    | 20 
2  | 453   | 1    | 30 
3  | 42   | 1    | 50 
4  | 12   | 2    | 12 
5  | 60   | 2    | 20 

想象一下，你需要列出拍賣其一定的人目前競標，失去。

因此，我們目前的用戶ID爲12，所以bid_from_user='12'

目前該用戶正在競標拍賣的ID 2與價格12和明顯失去，因爲有在同一拍賣的另一用戶投標具有更高的性價比。

我不想列出用戶所投標的所有拍賣，我只想列出那些用戶在和上失敗（=不是他獲勝的那些）。

那麼，我跑什麼樣的查詢來做到這一點？

Answer 1

SELECT b.bid_id, b.bid_from_user, b.bid_for_auction, b.bid_price 
    FROM bids b 
WHERE b.bid_from_user = '12' 
    AND EXISTS (
      SELECT 1 
      FROM bids x 
      WHERE x.bid_for_auction = b.bid_for_auction 
       AND x.bid_price > b.bid_price 
       AND x.bid_from_user <> b.bid_from_user); 

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編輯：上述似乎是最清潔，最清晰的溶液;但這裏是津貼爲MySQL歷來沒有處理好子查詢的替代...

SELECT b.bid_for_auction 
    FROM bids b 
     JOIN bids x ON x.bid_for_auction = b.bid_for_auction 
    AND x.bid_price > b.bid_price 
    AND x.bid_from_user <> b.bid_from_user 
    WHERE b.bid_from_user = '12' 
GROUP BY b.bid_for_auction; 

Answer 2

在選擇的值只爲證明：

SELECT MAX(a.bid_price), a.bid_for_auction, b.bid_price 
    FROM bids a 
     INNER JOIN bids b ON a.bid_for_auction = b.bid_for_auction 
    WHERE b.bid_from_user = 12 
GROUP BY bid_for_auction 
    HAVING b.bid_price < MAX(a.bid_price);