2016-12-01 117 views
-1

圖片: More information about the structure of the tables "offer" and "bid". Also a "Expected result" wich is shown the result. <-- really Important我怎樣才能顯示所有「文章」至少有3個「出價」?

我想表明的是有3個以上「投標」所有的「報價」的「ArticleName的」。應該輸出「投標」的數量。 我不知道如何寫下來。但我想我知道邏輯。它應該統計表格「出價」和列「OID」的相同數量,最後它應該粘貼大於3的數字。我想真正學習SQL,你知道一個頁面很容易理解?

我希望你能幫助我。

問候 綠茶

回答

0
SELECT * FROM (
    SELECT o.ArticleName, count(b.BID) as numberOfBids 
    FROM Offer as o INNER JOIN bid as b ON o.oid = b.oid 
    GROUP BY o.ArticleName 
) as c 
WHERE c.numberOfBids > 3 
0

嗯,這是很容易:

Select ArticleName 
    , count(*) NumberOfBids 
    from Offer o 
    join Bid b 
    on b.oid = o.oid 
group by ARticleName 
having count(*) >= 3 
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