我有这张表,可以称之为表一。对MySQL数据进行分组
+----+---------+-----------------+
| id | link_id | url |
+----+---------+-----------------+
| 1 | 1 | www.example.com |
| 2 | 1 | www.abc.com |
| 3 | 1 | www.test.com |
| 4 | 1 | www.t1.com |
| 5 | 1 | www.newtest.com |
| 6 | 1 | www.testing.com |
| 7 | 1 | www.abc.com |
| 8 | 1 | www.example.com |
| 9 | 1 | www.web1.com |
| 10 | 1 | www.web2.com |
| 11 | 2 | www.dear.com |
| 12 | 2 | www.google.com |
| 13 | 2 | www.flowers.com |
| 14 | 2 | www.yahoo.com |
| 15 | 2 | www.abc.com |
| 16 | 2 | www.dell.com |
| 17 | 2 | www.web.com |
| 18 | 2 | www.example.com |
| 19 | 2 | www.test.com |
| 20 | 2 | www.abc.com |
+----+---------+-----------------+
20 rows in set (0.00 sec)
link_id是排序表中的主标识符。它告诉我哪些URL出现在链接1,链接2等
我想acomplish是: 1.获取所有的唯一URL, 2显示该链接的URL属于
所以示例输出将是:
+-----------------+---------+
| url | link_id |
+-----------------+---------+
| www.example.com | 1 |
| www.example.com | 2 |
| www.abc.com | 1 |
| www.abc.com | 2 |
| www.test.com | 1 |
| www.test.com | 2 |
| www.t1.com | 1 |
| www.newtest.com | 1 |
| www.testing.com | 1 |
| www.web1.com | 1 |
...等等。
所以你可以看到,因为它是用两个链接1和2相关www.example.com出现了两次,但web1.com只出现一次,因为它只属于链接1.
我尝试了好几种不同的group by
但我最终只能挠挠我的脑袋。
任何帮助表示赞赏。下面是表转储如果有人需要:
CREATE TABLE IF NOT EXISTS `table1` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`link_id` tinyint(3) unsigned DEFAULT NULL,
`url` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=21 ;
INSERT INTO `table1` (`id`, `link_id`, `url`) VALUES
(1, 1, 'www.example.com'),
(2, 1, 'www.abc.com'),
(3, 1, 'www.test.com'),
(4, 1, 'www.t1.com'),
(5, 1, 'www.newtest.com'),
(6, 1, 'www.testing.com'),
(7, 1, 'www.abc.com'),
(8, 1, 'www.example.com'),
(9, 1, 'www.web1.com'),
(10, 1, 'www.web2.com'),
(11, 2, 'www.dear.com'),
(12, 2, 'www.google.com'),
(13, 2, 'www.flowers.com'),
(14, 2, 'www.yahoo.com'),
(15, 2, 'www.abc.com'),
(16, 2, 'www.dell.com'),
(17, 2, 'www.web.com'),
(18, 2, 'www.example.com'),
(19, 2, 'www.test.com'),
(20, 2, 'www.abc.com');
为漂亮的桌子+1。 – GSerg 2011-05-05 16:44:39