在SELECT语句中用另一个表替换另一个值

Question

我试图想出一个SQL语句来打印Puppet数据库中的所有重复[导出资源]定义。

mysql> SELECT id,restype,host_id,source_file_id FROM resources  
    -> WHERE title IN (SELECT title FROM resources WHERE exported=1 
    -> GROUP BY title HAVING count(title) > 1) ORDER BY title; 
+------+------------------------+---------+----------------+ 
| id | restype    | host_id | source_file_id | 
+------+------------------------+---------+----------------+ 
| 305 | Nagios::Client::Export |  2 |    18 | 
| 333 | Nagios_host   |  2 |    39 | 
| 605 | Nagios_hostextinfo  |  6 |    2 | 
| 443 | Nagios_hostextinfo  |  2 |    39 | 
| 499 | Nagios_host   |  6 |    2 | 
| 770 | Nagios::Client::Export |  6 |    18 | 
...... 
...... 

这是工作得很好，但我怎么能检索/打印hosts.name从主机表中host_id代替。我只是无法重写上面的SQL语句。该主机表看起来像这样：

mysql> SELECT id,name FROM hosts; 
+----+-----------------------------------------+ 
| id | name         | 
+----+-----------------------------------------+ 
| 2 | controller-dns-01.sdas.cloud.com  | 
| 6 | controller-monitoring-01.sdas.cloud.com | 
| 1 | controller-puppet.sdas.cloud.com  | 
| 13 | talend-admin-01.sdas.cloud.com   | 
| 15 | talend-jobserver-01.sdas.cloud.com  | 
| 14 | talend-jobserver-02.sdas.cloud.com  | 
+----+-----------------------------------------+ 

此外，有没有办法只打印在整个字符串代替的主机名（即仅controller-dns-01）的第一部分？任何人的任何建议不胜感激。干杯！！

---

更新：
这是我最后的命令：就在情况下，如果别人也在寻找一种方式来找出木偶导出的资源重复定义

mysql> CREATE INDEX index_resources_on_restypetitle ON resources (restype(12),title(12)); 
mysql> SELECT r.id, r.restype, r.title, SUBSTRING_INDEX(h.name,'.',1) AS 'host_name', 
    -> SUBSTRING_INDEX(s.filename,'puppet/',-1) AS 'file_name', r.line FROM resources r 
    -> LEFT JOIN hosts h ON r.host_id = h.id LEFT JOIN source_files s ON r.source_file_id = s.id 
    -> WHERE MD5(CONCAT(restype,title,host_id)) 
    -> IN (SELECT MD5(CONCAT(restype,title,host_id)) FROM resources 
    -> WHERE exported=1 GROUP BY MD5(CONCAT(restype,title,host_id)) 
    -> HAVING COUNT(MD5(CONCAT(restype,title,host_id))) > 1) ORDER BY title; 

的SUBSTRING_INDEX(s.filename....)位可能需要根据配置重新调整。非常感谢thiella帮助我。

Answer 1

你需要与你的hosts表加入您的resources表，使用SUBSTRING_INDEX在点的左边显示字符串的一部分：

SELECT 
    r.id, r.restype, r.host_id, r.source_file_id, 
    SUBSTRING_INDEX(h.name, '.', 1) 
FROM 
    resources r LEFT JOIN hosts h 
    ON r.host_id = h.id 
WHERE 
    r.title IN (SELECT title 
      FROM resources 
      WHERE export=1 
      GROUP BY title 
      HAVING count(title) > 1) 
ORDER BY 
    r.title;