Php 如何创建一个奇特的mysql连接，它可以连接三个表，并检测一个表是否没有我的项

php mysql查询 我有多个链接表-我还有一个表，只有在存在特定条件时才创建和输入，所以我想将其添加到我的查询中，以避免需要通过数千次查询搜索来查找这种特殊情况

这是我目前的问题

$query = "SELECT a.UUID FROM contract a 
        INNER JOIN geoPoint b ON a.customer_UUID = b.customerUUID
        WHERE b.garcom_UUID = '$garbCom'
        AND b.city_UUID = '$city'";

然后，我检查了返回的每个项目（以千为单位）

而不是所有这些，我只想让它成为一个查询-psedoo代码类似这样的东西

 $query = "SELECT a.UUID FROM contract a 
            INNER JOIN geoPoint b ON a.customer_UUID = b.customerUUID
            INNER JOIN contract_sales c ON a.UUID = c.contractUUID
            WHERE b.garcom_UUID = '$garbCom'
            AND b.city_UUID = '$city' AND c.DOESNOTEXIST";

这样我就不必返还数千美元，我只会返还合同销售表中还没有的那几笔，我可以继续我的生意

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谢谢你的帮助

我认为这是一个左外连接问题

看看这个例子。您特别需要检查表中要查找缺少rof行的列中是否有null

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我认为这是一个左外连接问题

看看这个例子。您特别需要检查表中要查找缺少rof行的列中是否有null

---

听起来好像

不存在

相关子查询就是您需要的：

$query = "SELECT a.UUID FROM contract a 
            INNER JOIN geoPoint b ON a.customer_UUID = b.customerUUID
            WHERE b.garcom_UUID = '$garbCom'
            AND b.city_UUID = '$city' 
            AND NOT EXISTS (SELECT 1 
                              FROM contract_sales c
                              WHERE c.contractUUID = a.UUID)";

---

听起来好像

不存在

您需要的是相关子查询：

$query = "SELECT a.UUID FROM contract a 
            INNER JOIN geoPoint b ON a.customer_UUID = b.customerUUID
            WHERE b.garcom_UUID = '$garbCom'
            AND b.city_UUID = '$city' 
            AND NOT EXISTS (SELECT 1 
                              FROM contract_sales c
                              WHERE c.contractUUID = a.UUID)";

---

只需检查带有

外部联接的
c行的
NULL

$query = "SELECT a.UUID FROM contract a 
        INNER JOIN geoPoint b ON a.customer_UUID = b.customerUUID
        LEFT OUTER JOIN contract_sales c ON a.UUID = c.contractUUID
        WHERE b.garcom_UUID = '$garbCom'
        AND b.city_UUID = '$city' AND c.contractUUID IS NULL ";

只需检查带有
外部联接的
c行的
NULL

$query = "SELECT a.UUID FROM contract a 
        INNER JOIN geoPoint b ON a.customer_UUID = b.customerUUID
        LEFT OUTER JOIN contract_sales c ON a.UUID = c.contractUUID
        WHERE b.garcom_UUID = '$garbCom'
        AND b.city_UUID = '$city' AND c.contractUUID IS NULL ";

表结构是什么样的，它们是如何关联的？表结构是什么样的，它们是如何关联的？工作非常完美，比其他解决方案少得多，谢谢！工作完美，比其他解决方案少得多，谢谢！