极客教程如何从MySQL结果中选择第一行和最后一行数据？
您可以使用MIN（）和MAX（）选择第一行和最后一行数据。 语法如下 −
SELECT *
FROM yourTableName
WHERE yourColumnName = (SELECT MIN(yourColumnName) FROM yourTableName)
UNION
SELECT *
FROM yourTableName
WHERE yourColumnName = (SELECT MAX(yourColumnName) FROM yourTableName) ;
为了理解上述语法，让我们创建一个表。创建表的查询如下 −
mysql> create table FirstAndLastDataDemo
-> (
-> EmployeeId int NOT NULL AUTO_INCREMENT PRIMARY KEY,
-> EmployeeName varchar(20),
-> EmployeeAge int
-> );
Query OK, 0 rows affected (0.59 sec)
阅读更多：MySQL 教程
示例
使用INSERT命令在表中插入一些记录。查询如下 −
mysql> insert into FirstAndLastDataDemo(EmployeeName,EmployeeAge) values('John',23);
Query OK, 1 row affected (0.15 sec)
mysql> insert into FirstAndLastDataDemo(EmployeeName,EmployeeAge) values('Bob',13);
Query OK, 1 row affected (0.11 sec)
mysql> insert into FirstAndLastDataDemo(EmployeeName,EmployeeAge) values('Larry',24);
Query OK, 1 row affected (0.14 sec)
mysql> insert into FirstAndLastDataDemo(EmployeeName,EmployeeAge) values('Sam',14);
Query OK, 1 row affected (0.18 sec)
mysql> insert into FirstAndLastDataDemo(EmployeeName,EmployeeAge) values('Mike',31);
Query OK, 1 row affected (0.10 sec)
mysql> insert into FirstAndLastDataDemo(EmployeeName,EmployeeAge) values('James',18);
Query OK, 1 row affected (0.16 sec)
mysql> insert into FirstAndLastDataDemo(EmployeeName,EmployeeAge)
values('Maxwell',28);
Query OK, 1 row affected (0.17 sec)
mysql> insert into FirstAndLastDataDemo(EmployeeName,EmployeeAge) values('David',27);
Query OK, 1 row affected (0.12 sec)
mysql> insert into FirstAndLastDataDemo(EmployeeName,EmployeeAge) values('Chris',22);
Query OK, 1 row affected (0.19 sec)
使用SELECT语句显示表中的所有记录 −
mysql> select *from FirstAndLastDataDemo;
输出
+------------+--------------+-------------+
| EmployeeId | EmployeeName | EmployeeAge |
+------------+--------------+-------------+
| 1 | John | 23 |
| 2 | Bob | 13 |
| 3 | Larry | 24 |
| 4 | Sam | 14 |
| 5 | Mike | 31 |
| 6 | James | 18 |
| 7 | Maxwell | 28 |
| 8 | David | 27 |
| 9 | Chris | 22 |
+------------+--------------+-------------+
9 rows in set (0.00 sec)
这是获取第一行数据和最后一行数据的查询语句 −
mysql> SELECT *
-> FROM FirstAndLastDataDemo
-> WHERE EmployeeId = (SELECT MIN(EmployeeId) FROM FirstAndLastDataDemo)
-> UNION
-> SELECT *
-> FROM FirstAndLastDataDemo
-> WHERE EmployeeId = (SELECT MAX(EmployeeId) FROM FirstAndLastDataDemo);
输出
+------------+--------------+-------------+
| EmployeeId | EmployeeName | EmployeeAge |
+------------+--------------+-------------+
| 1 | John | 23 |
| 9 | Chris | 22 |
+------------+--------------+-------------+
2 rows in set (0.00 sec)