我应该运行什么查询来为 SQL 表中的每组值选择最高值？

Question

我有一个出价表（例如 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

我只需选择每个bid_for_auction一次及其当前最高出价，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

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

Answer 3

这应该可以解决问题：

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