我有几个（MySQL）表。有趣的是CampaignRegion，它存储到Campaign的外键和一个到City，County，District，State或Country的外键。始终只有一个特定于位置的外键集，其他的是NULL。CampaignRegion表如下所示：mysql> describe CampaignRegion;+-------------+---------+------+-----+---------+----------------+| Field | Type | Null | Key | Default | Extra |+-------------+---------+------+-----+---------+----------------+| id | int(11) | NO | PRI | NULL | auto_increment || campaign_id | int(11) | YES | MUL | NULL | || country_id | int(11) | YES | MUL | NULL | || state_id | int(11) | YES | MUL | NULL | || district_id | int(11) | YES | MUL | NULL | || county_id | int(11) | YES | MUL | NULL | || city_id | int(11) | YES | MUL | NULL | |+-------------+---------+------+-----+---------+----------------+我现在需要一个查询来选择Campaign。我有一个City，需要获取与Campaigns本身或City或County或District或State的Country匹配的City。这实际上非常容易，我想出了类似以下内容：SELECT count(id) as campaign_count, campaign_id FROM CampaignRegion WHERE (city_id = 32076 OR district_id = 127 OR state_id = 7 OR country_id = 156) GROUP BY campaign_idHAVING campaign_count > 0;但是我想得到的Campaigns结果集首先与City匹配，然后与County匹配，然后与District匹配，依此类推（例如中有一个简单的方法吗？我会根据OR或SELECT中的此查询对Campaign（第一个匹配的）JOIN做些什么呢？谢谢您的帮助。 最佳答案 我认为这是您要寻找的：SELECT count(id) as campaign_count, campaign_idFROM CampaignRegionWHERE (city_id = 32076 OR district_id = 127 OR state_id = 7 OR country_id = 156)GROUP BY campaign_idHAVING campaign_count > 0;ORDER BY (city_id = 32076) DESC, (country_id = 156) DESC, (state_id = 7) DESC, (district_id = 127) DESC;关于mysql - 查找与一个字段匹配的相关实体，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/11825681/
