如何在MySQL表中仅选择3个有序行？

为此，可以使用ORDER BY子句以及LIMIT。让我们首先创建一个表 –

mysql> create table DemoTable1551
   -> (
   -> EmployeeId int NOT NULL AUTO_INCREMENT PRIMARY KEY,
   -> EmployeeName varchar(20)
   -> );
Query OK, 0 rows affected (0.52 sec)

使用插入命令将一些记录插入表中 –

mysql> insert into DemoTable1551(EmployeeName) values('Chris');
Query OK, 1 row affected (0.25 sec)
mysql> insert into DemoTable1551(EmployeeName) values('Robert');
Query OK, 1 row affected (0.13 sec)
mysql> insert into DemoTable1551(EmployeeName) values('Mike');
Query OK, 1 row affected (0.12 sec)
mysql> insert into DemoTable1551(EmployeeName) values('Sam');
Query OK, 1 row affected (0.11 sec)
mysql> insert into DemoTable1551(EmployeeName) values('David');
Query OK, 1 row affected (0.09 sec)
mysql> insert into DemoTable1551(EmployeeName) values('Adam');
Query OK, 1 row affected (0.11 sec)

使用SELECT语句显示表中的所有记录 –

mysql> select * from DemoTable1551;

这将产生以下输出 –

+------------+--------------+
| EmployeeId | EmployeeName |
+------------+--------------+
|          1 | Chris        |
|          2 | Robert       |
|          3 | Mike         |
|          4 | Sam          |
|          5 | David        |
|          6 | Adam         |
+------------+--------------+
6 rows in set (0.00 sec)

以下是在MySQL表中选择仅三个有序行的查询 –

mysql> select * from DemoTable1551
   -> order by EmployeeId desc limit 0,3;

这将产生以下输出 –

+------------+--------------+
| EmployeeId | EmployeeName |
+------------+--------------+
|          6 | Adam         |
|          5 | David        |
|          4 | Sam          |
+------------+--------------+
3 rows in set (0.00 sec)

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