如何在 MySQL 中使用 LIMIT 选择第一行和最后一行记录?
我们首先创建一个表。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)
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;
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,查询如下
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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