LEFT加入SQL需要5分钟并崩溃

Question

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我有一个代理权表,与地区,国家,地区,城市,行业,专业,行业,专业和次专业有着多对多的关系.

办公室和联系人之间也存在一对多的关系.

基本上我想要做的是创建一个显示这些表中特定记录的结果表.

我已经在表中的每个外键上创建了索引.这是我的查询:

SELECT agencies.agency, 
       agencies.website_url, 
       agencies.status, 
       agencies.SIZE, 
       agencies.id, 
       officedata.id, 
       contactdata.name, 
       contactdata.surname, 
       contactdata.job_title, 
       contactdata.email, 
       contactdata.mobile 
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 
       LEFT JOIN (SELECT agencies_countries.agency_id, 
                         agencies_countries.country_id 
                  FROM   agencies_countries) AS countrydata 
         ON agencies.id = countrydata.agency_id 
       LEFT JOIN (SELECT agencies_regions.agency_id, 
                         agencies_regions.region_id 
                  FROM   agencies_regions) AS regiondata 
         ON agencies.id = regiondata.agency_id 
       LEFT JOIN (SELECT agencies_cities.agency_id, 
                         agencies_cities.city_id 
                  FROM   agencies_cities) AS citydata 
         ON agencies.id = citydata.agency_id 
       LEFT JOIN (SELECT agencies_specialisms.agency_id, 
                         agencies_specialisms.specialism_id 
                  FROM   agencies_specialisms) AS specialismdata 
         ON agencies.id = specialismdata.agency_id 
       LEFT JOIN (SELECT agencies_sub_specialisms.agency_id, 
                         gencies_sub_specialisms.sub_specialism_id 
                  FROM   agencies_sub_specialisms) AS subdata 
         ON agencies.id = subdata.agency_id 
       LEFT JOIN (SELECT offices.id, 
                         offices.agency_id, 
                         offices.hq 
                  FROM   offices 
                  WHERE  offices.hq = "1") AS officedata 
         ON agencies.id = officedata.agency_id 
       LEFT JOIN (SELECT contacts.name, 
                         contacts.surname, 
                         contacts.agency_id, 
                         contacts.job_title, 
                         contacts.email, 
                         contacts.mobile 
                  FROM   contacts) AS contactdata 
         ON agencies.id = contactdata.agency_id 

执行时,站点加载并加载,5分钟后崩溃.我不知道为什么需要这么长时间.在phpMyAdmin的过程中,它说"复制到tmp表".在终止此进程后,站点将完成加载错误.有时在执行此查询后整个phpMyAdmin不起作用.

你知道如何让它正常工作吗？

PS

在数据库中,每个表中只有大约20行或更少的行.另外,当最后使用伪数据提供WHERE子句时,查询将在10秒内执行,显示无结果.当我提供仅适合一个结果的数据时,它在大约20秒内执行.

更新

好的抱歉我接受了答案太快,因为我没有解释为什么我需要离开加入那些在我之前的例子中没有使用过的表.

关键是我也需要使用它们,因为所有这些都是一个搜索系统 - 有人想搜索一个区域是非洲的代理商 - 在结果中它没有显示但需要被选中.

当我将查询更改为:

SELECT agencies.agency
                    ,agencies.website_url
                    ,agencies.STATUS
                    ,agencies.size
                    ,agencies.id
                    ,agencies.status
                    ,OfficeData.id
                    ,ContactData.name
                    ,ContactData.surname
                    ,ContactData.job_title
                    ,ContactData.email
                    ,ContactData.mobile
                    FROM agencies
                    LEFT JOIN offices AS OfficeData ON agencies.id = OfficeData.agency_id
                    AND OfficeData.hq = "1"
                    LEFT JOIN contacts AS ContactData ON agencies.id = ContactData.agency_id
                    LEFT JOIN agencies_professions AS ProfessionData ON agencies.id = ProfessionData.agency_id
                    LEFT JOIN agencies_seniorities AS SeniorityData ON agencies.id = SeniorityData.agency_id
                    LEFT JOIN agencies_sectors AS SectorData ON agencies.id = SectorData.agency_id
                    LEFT JOIN agencies_countries AS CountryData ON agencies.id = CountryData.agency_id
                    LEFT JOIN agencies_regions AS RegionData ON agencies.id = RegionData.agency_id
                    LEFT JOIN agencies_sub_specialisms AS SubData ON agencies.id = SubData.agency_id
                    LEFT JOIN agencies_cities AS CityData ON agencies.id = CityData.agency_id
                    LEFT JOIN agencies_zones AS ZoneData ON agencies.id = ZoneData.agency_id
                    LEFT JOIN agencies_specialisms AS SpecialismData ON agencies.id = SpecialismData.agency_id
                    LEFT JOIN agencies_industries AS IndustryData ON agencies.id = IndustryData.agency_id

它仍然加载直到崩溃服务器.

在这个过程中它现在说"发送数据"

Answer 1

您的查询有两个问题.1)有许多不必要的子选择.2)您在从未从中选择数据的表上进行LEFT JOIN.

试试这个:

SELECT agencies.agency
    ,agencies.website_url
    ,agencies.STATUS
    ,agencies.size
    ,agencies.id
    ,OfficeData.id
    ,ContactData.NAME
    ,ContactData.surname
    ,ContactData.job_title
    ,ContactData.email
    ,ContactData.mobile
FROM agencies
LEFT JOIN offices AS OfficeData ON agencies.id = OfficeData.agency_id
    AND OfficeData.hq = "1"
LEFT JOIN contacts AS ContactData ON agencies.id = ContactData.agency_id