MySQL中MIN()函数的使用教程

MySQL的MIN函数是用来找出一个记录集最小值的记录。

要了解MIN函数考虑的EMPLOYEE_TBL表具有以下记录：

mysql> SELECT * FROM employee_tbl;
+------+------+------------+--------------------+
| id  | name | work_date | daily_typing_pages |
+------+------+------------+--------------------+
|  1 | John | 2007-01-24 |        250 |
|  2 | Ram | 2007-05-27 |        220 |
|  3 | Jack | 2007-05-06 |        170 |
|  3 | Jack | 2007-04-06 |        100 |
|  4 | Jill | 2007-04-06 |        220 |
|  5 | Zara | 2007-06-06 |        300 |
|  5 | Zara | 2007-02-06 |        350 |
+------+------+------------+--------------------+
7 rows in set (0.00 sec)

现在假设上面的表的基础上想要取daily_typing_pages的最小值，那么可以这样做，简单地使用下面的命令：

mysql> SELECT MIN(daily_typing_pages)
  -> FROM employee_tbl;
+-------------------------+
| MIN(daily_typing_pages) |
+-------------------------+
|           100 |
+-------------------------+
1 row in set (0.00 sec)

可以找到所有记录的最小值按名字使用GROUP BY子句如下：

mysql> id, name, work_date, MIN(daily_typing_pages)
  -> FROM employee_tbl GROUP BY name;
+------+------+------------+-------------------------+
| id  | name | work_date | MIN(daily_typing_pages) |
+------+------+------------+-------------------------+
|  3 | Jack | 2007-05-06 |           100 |
|  4 | Jill | 2007-04-06 |           220 |
|  1 | John | 2007-01-24 |           250 |
|  2 | Ram | 2007-05-27 |           220 |
|  5 | Zara | 2007-06-06 |           300 |
+------+------+------------+-------------------------+
5 rows in set (0.00 sec)

您可以使用MIN函数和MAX函数一起，查找最小值。试试下面的例子：

mysql> SELECT MIN(daily_typing_pages) least, MAX(daily_typing_pages) max
  -> FROM employee_tbl;
+-------+------+
| least | max |
+-------+------+
|  100 | 350 |
+-------+------+
1 row in set (0.01 sec)