如何运行哪个查询以选择SQL表中每个值组的最高值？

Question

我有一张bids表（例如，像eBay出价）：

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

我需要选择每个bid_for_auction只与最高当前的出价一次 ，所以我的结果应该是这样的：

bid_for_auction | bid_price
1               | 50
2               | 20

我将如何去做呢？

Answer 1

使用GROUP BY

SELECT bid_for_auction, MAX(bid_price) AS bid_price
FROM bids GROUP BY bid_for_auction;

Answer 2

这应该可以解决问题：

SELECT
 `bid_for_auction`,
 MAX(`bid_price`)
FROM `bids`
GROUP BY `bid_for_auction`

Answer 3

SELECT bid_for_auction, MAX(bid_price)
FROM bids
GROUP BY bid_for_auction

Answer 4

SELECT bid_for_auction，MAX（bid_price）FROM bids GROUP BY bid_for_auction