如何使用MySQL中的LIMIT选择第一行和最后一行记录?
让我们首先创建一个表。创建表的查询如下所示:
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)
使用insert命令在表中插入一些记录。查询如下所示:
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;
以下是输出:
+------------+--------------+-------------+
| 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)
要使用LIMIT获取第一行和最后一行记录,请使用以下查询:
mysql> (SELECT *from FirstAndLastDataDemo LIMIT 1)
-> UNION
-> (SELECT *from FirstAndLastDataDemo LIMIT 8,1);
以下是显示第一行和最后一行记录的输出:
+------------+--------------+-------------+
| EmployeeId | EmployeeName | EmployeeAge |
+------------+--------------+-------------+
| 1 | John | 23 |
| 9 | Chris | 22 |
+------------+--------------+-------------+
2 rows in set (0.00 sec)
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