2

我有一张表用于存储半径服务器的所有访问请求，如下所示：

describe radius.loginattempts;
+------------------+------------------+------+-----+---------+----------------+
| Field            | Type             | Null | Key | Default | Extra          |
+------------------+------------------+------+-----+---------+----------------+
| loginattempt_key | int(10) unsigned | NO   | PRI | NULL    | auto_increment |
| log_date         | int(10) unsigned | NO   |     | NULL    |                |
| result           | tinyint(1)       | YES  |     | NULL    |                |
| username         | text             | YES  |     | NULL    |                |
| mac              | text             | YES  |     | NULL    |                |
+------------------+------------------+------+-----+---------+----------------+

每次有人尝试登录时，无论它是否有效，都会在此表中创建一个日志条目。

我想要做的是获取有两个或多个用户尝试登录的所有设备的列表，以及每个设备的所有不同用户名。

所以，如果我有一些看起来像这样的数据：

select * from loginattempts limit 8;
+------------------+------------+--------+----------+-------------------+
| loginattempt_key | log_date   | result | username | mac               |
+------------------+------------+--------+----------+-------------------+
|                1 | 1337035334 |      1 | kclark   | 11:11:11:11:11:11 |
|                2 | 1337035620 |      1 | kclark   | 22:22:22:22:22:22 |
|                3 | 1337035681 |      0 | guest    | 33:33:33:33:33:33 |
|                4 | 1337035740 |      1 | guest    | 22:22:22:22:22:22 |
|                5 | 1337037782 |      1 | rfogarty | 44:44:44:44:44:44 |
|                6 | 1337037789 |      1 | jsmith   | 44:44:44:44:44:44 |
|                7 | 1337037790 |      1 | jsmith   | 44:44:44:44:44:44 |
|                8 | 1337037791 |      1 | jsmith   | 44:44:44:44:44:44 |
+------------------+------------+--------+----------+-------------------+

我想要一个返回如下内容的魔术查询：

+-------------------+----------+
| mac               | username |
+-------------------+----------+
| 22:22:22:22:22:22 | kclark   |
| 22:22:22:22:22:22 | guest    |
| 44:44:44:44:44:44 | rfogarty |
| 44:44:44:44:44:44 | jsmith   |
+-------------------+----------+

这最终将在 PHP 中，我可以通过两个查询和一个 for 循环轻松完成，但作为一个思想实验，我一直在尝试考虑如何使用单个查询和一些花哨的连接（甚至是子查询）来完成）但就是无法绕开我的头......

mysql -V
mysql  Ver 14.14 Distrib 5.1.52, for unknown-linux-gnu (x86_64) using readline 5.1
4

1 回答 1

1

好的，我想你的意思是...... http://sqlfiddle.com/#!3/b6100/6

给定

create table loginattempts  
(
  login_key int,
  mac varchar(12) null,
  username varchar(12) null
)

insert into loginattempts values (1, 111, 'peter')
insert into loginattempts values (2, 111, 'bob')
insert into loginattempts values (3, 222, 'geoff')
insert into loginattempts values (4, 222, 'lisa')
insert into loginattempts values (1, 333, 'peter')

你需要这个查询

   select mac, username
   from loginattempts
   where
    mac in
    (
      select mac
      from loginattempts
      group by mac
      having count(*) > 1
     )

给你

MAC USERNAME
111 peter
111 bob
222 geoff
222 lisa
于 2012-05-17T17:28:02.340 回答