Question

用户表：

id | name
1 | sai
2 | krishna

出价表：

bid_id | listing_id | user_id | bid_amount
1 | 999 | 1 | 100
2 | 999 | 2 | 200
3 | 999 | 2 | 300

所以我希望得到的结果就是这个

bid_id | listing_id | bid_amount | name
1      | 999        | 100        | sai
3      | 999        | 300        | krishna

我希望结果按listing_id分组，但只为bid_amount为最大值的用户显示不同的行

Answer 1

SELECT COALESCE(b1.bid_id, -1),
       COALESCE(b1.listing_id, -1),
       COALESCE(b1.bid_amount, 0),
       u.name
FROM user u
LEFT JOIN bid b1
    ON u.id = b1.user_id
LEFT JOIN
(
    SELECT user_id, MAX(bid_amount) AS bid_amount
    FROM bid
    GROUP BY user_id
) b2
    ON b1.user_id    = b2.user_id AND
       b1.bid_amount = b2.bid_amount

Answer 2

有一个派生表（子查询），它返回每个列表的最高出价。加入该结果并加入用户：

select b1.bid_id, b1.listing_id, b2.bid_amount, u.name
from bid b1
join (select listing_id, max(bid_amount) as max_bid_amount
      from bid
      group by listing_id) b2
     on b1.listing_id = b2.listing_id and b1.bid_amount = b2.max_bid_amount
join user u on b.user_id = u.id

Answer 3

这应该做：

SELECT      bid.bid_id, bid.listing_id, bid.bid_amount, users.name
FROM        bid bid
INNER JOIN  user users ON bid.user_id = users.id
INNER JOIN  (SELECT     MAX(bid.bid_amount) AS MaxBid, bid.user_id
             FROM       bid bid
             GROUP BY   bid.user_id
             ) MaxBids ON bid.bid_amount = MaxBids.MaxBid

Answer 4

Select      D1.*
From        (
            Select      D1.id, D1.name, D2.bid_id, D2.listing_id, D2.bid_amount,
                        Rank() Over (Partition By D1.id
                                    order by D2.bid_amount desc
                                    )  As Rank
            From        @table1 D1
            Inner Join  @table2 D2
                On      D1.id = D2.user_id
            ) D1
Where       D1.Rank =1

结果按一列分组，并根据第二列的最大值显示不同的行

4 个答案: