如何将这两个查询合并为比较查询

dlofrodloh 发表于 Dev

dlofrodloh

目前，我有以下两个查询：

"SELECT company.id, company.name, 
        contact.firstname, contact.lastname, 
        contact.email, contact.id AS contactid
   from ecampaign_lookup
   LEFT JOIN company ON ecampaign_lookup.companyid=company.id 
   LEFT JOIN contact ON ecampaign_lookup.contactid=contact.id
  WHERE ecampaign_lookup.campaignid=".$tid;

和：

"SELECT company.id, company.name, 
         contact.firstname, contact.lastname, 
         contact.email, contact.id AS contactid
   from ecampaign_lookup
   LEFT JOIN company ON ecampaign_lookup.companyid=company.id 
   LEFT JOIN contact ON contact.companyid=company.id
  WHERE ecampaign_lookup.campaignid=".$tid." 
    AND contact.defaultcontact=1";

不同之处在于，第一个查询从“ ecampaign_lookup”表返回联系人，第二个查询从“ company”表返回联系人。第二个查询还要求仅选择'contact.defaultcontact = 1'的联系人，因为每个公司有很多联系人，但每个ecampaign_lookup只有一个联系人。

目前，我分别运行这两个查询，然后使用for循环比较结果，如果一个查询的返回值小于或大于另一个查询，则很容易出错：

        for ($x=0;$x<count($query1_result);$x++){
                if ($query1_result[$x]['contactid']!=$query2_result[$x]['contactid']){
                     echo $query1_result[$x]['firstname']." has been replaced by ".
                     $query2_result[$x]['firstname'];   
                }
        }

如何将两个查询合并在一起，以将ecampaign_lookup.contactid与第二个查询中的contact.id进行比较，并且仅返回两个不匹配的结果？

dlofrodloh

好的，经过反复尝试，我找到了使用子查询的解决方案：

 SELECT company.id,
       company.NAME,
       contact.firstname,
       contact.lastname,
       contact.email,
       contact.id AS contactid
FROM   ecampaign_lookup
       LEFT JOIN company
              ON ecampaign_lookup.companyid = company.id
       LEFT JOIN contact
              ON contact.companyid = company.id
WHERE  ecampaign_lookup.campaignid = :tid
       AND contact.defaultcontact = 1
       AND contact.id NOT IN (SELECT contact.id AS contactid
                              FROM   ecampaign_lookup
                                     LEFT JOIN company
                                            ON
                                     ecampaign_lookup.companyid = company.id
                                     LEFT JOIN contact
                                            ON
                                     ecampaign_lookup.contactid = contact.id
                                     WHERE  ecampaign_lookup.campaignid = :tid)