从GROUP BY获取最高或最低值的行

本文介绍了从GROUP BY获取最高或最低值的行的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我试图在执行 GROUP BY 后获得最高/最低编号的行：

I'm trying to get the row with the highest/lowest number, after performing a GROUP BY:

这是我的测试数据

mysql> SELECT * FROM test; +----+-------+------+ | id | value | name | +----+-------+------+ | 1 | 10 | row1 | | 2 | 12 | row2 | | 3 | 10 | row2 | | 4 | 5 | row2 | +----+-------+------+ 4 rows in set (0.00 sec)

为了得到最小值，我将使用 MIN（）

To get the lowest value, I'll use MIN()

mysql> SELECT id, name, MIN(value) AS value FROM test GROUP BY name; +----+------+-------+ | id | name | value | +----+------+-------+ | 1 | row1 | 10 | | 2 | row2 | 5 | +----+------+-------+ 2 rows in set (0.00 sec)

现在，id row2 是 2 ，但它应该是 4 。

Now, the id row2 is 2, but it should be 4.

我也尝试了一个连接：

I also tried with a join:

mysql> SELECT t1.* FROM (SELECT id, name, MIN(value) AS value FROM test GROUP BY name) AS t1 INNER JOIN test AS t2 ON t1.id = t2.id; +----+------+-------+ | id | name | value | +----+------+-------+ | 1 | row1 | 10 | | 2 | row2 | 5 | +----+------+-------+ 2 rows in set (0.00 sec)

如何根据最低值的结果得到每个结果的正确ID？

How can I get the correct ID for each result based on what the lowest value is?

推荐答案

我认为这就是您要实现的目标：

I think this is what you are trying to achieve:

SELECT t.* FROM test t JOIN ( SELECT Name, MIN(Value) minVal FROM test GROUP BY Name ) t2 ON t.Value = t2.minVal AND t.Name = t2.Name;

输出：

╔════╦═══════╦══════╗ ║ ID ║ VALUE ║ NAME ║ ╠════╬═══════╬══════╣ ║ 1 ║ 10 ║ row1 ║ ║ 4 ║ 5 ║ row2 ║ ╚════╩═══════╩══════╝

请参阅 this SQLFiddle

• 具有更多价值的演示
• 具有重复值的演示
• 删除重复值的演示（使用 DISTINCT ）

See this SQLFiddle

• Demo with more values
• Demo with duplicate values
• Demo with removing duplicate values (using DISTINCT)

这里我用minVal和Name自加入表。

Here I have self-joined the table with minVal and Name.