获取唯一值作为查询结果

Question

我与我的数据库有多对多的关系，所以我创建了一个sql查询，稍后我将用于搜索。 现在我想要做的是从我的搜索结果（独特的公司名称）中获取唯一的值。

这是我的查询：

SELECT agencies.company 
    ,agencies.website_url 
    ,agencies.STATUS 
    ,agencies.size 
    ,IndustryData.industry_id 
    ,ProfessionData.profession_id 
    ,SectorData.sector_id 
    ,seniorityData.seniority_id 
    ,ZonesData.zone_id 
FROM agencies 
LEFT JOIN (
    SELECT agencies_industries.agency_id 
     ,agencies_industries.industry_id 
    FROM agencies_industries 
    ) AS IndustryData ON agencies.id = IndustryData.agency_id 
LEFT JOIN (
    SELECT agencies_professions.agency_id 
     ,agencies_professions.profession_id 
    FROM agencies_professions 
    ) AS ProfessionData ON agencies.id = ProfessionData.agency_id 
LEFT JOIN (
    SELECT agencies_sectors.agency_id 
     ,agencies_sectors.sector_id 
    FROM agencies_sectors 
    ) AS SectorData ON agencies.id = SectorData.agency_id 
LEFT JOIN (
    SELECT agencies_seniorities.agency_id 
     ,agencies_seniorities.seniority_id 
    FROM agencies_seniorities 
    ) AS SeniorityData ON agencies.id = SeniorityData.agency_id 
LEFT JOIN (
    SELECT agencies_zones.agency_id 
     ,agencies_zones.zone_id 
    FROM agencies_zones 
    ) AS ZonesData ON agencies.id = ZonesData.agency_id 
WHERE IndustryData.industry_id = 3 
    AND ProfessionData.profession_id = 1 

结果看起来是这样的：

公司，WEBSITE_URL，状态，大小，industry_id，profession_id，sector_id，seniority_id，zone_id

1. Nine nine.com 1 3 3 1 3 2 1
2. Nine nine.com 1 3 3 1 3 2 5
3. 九nine.com 1 3 3 1 3 2 8
4. 九nine.com 1 3 3 1 3 5 1
5. 九nine.com 1 3 3 1 3 5 5
6. 九nine.com 1 3 3 1 3 5 8
7. 十ten.com 2 3 3 1 3 1 1
8. 十ten.com 2 3 3 1 3 1 3
9. 十ten.com 2 3 3 1 3 1 7
10. Ten ten.com 2 3 3 1 3 3 1
11. Ten ten.com 2 3 3 1 3 3 3
12. 十ten.com 2 3 3 1 3 3 7
13. 十ten.com 2 3 3 1 3 5 1
14. 十ten.com 2 3 3 1 3 5 3
15. 十ten.com 2 3 3 1 3 5 7

我想摆脱公司名称的重复。我怎么做？

Answer 1

你可以使用一个GROUP BY为此，例如：

SELECT agencies.company 
    ,agencies.website_url 
    ,agencies.STATUS 
    ,agencies.size 
    ,IndustryData.industry_id 
    ,ProfessionData.profession_id 
    ,SectorData.sector_id 
FROM ... 
GROUP BY agencies.company 
    ,agencies.website_url 
    ,agencies.STATUS 
    ,agencies.size 
    ,IndustryData.industry_id 
    ,ProfessionData.profession_id 
    ,SectorData.sector_id 

Answer 2

也许你可以做到这一点与变量和子查询，如下所示一些例子：

http://dev.mysql.com/doc/refman/5.0/en/user-variables.html

但也许这样你的代码比您的查询速度更快。