Question

我有一个带有多个连接的SQL语句，可以完全没有任何问题

$sql = "SELECT ni.*, GROUP_CONCAT(DISTINCT newsletter_item_receivers.value ORDER BY newsletter_item_receivers.value) AS receivers, nf.*, GROUP_CONCAT(DISTINCT nm.mailgroup_name ORDER BY nm.mailgroup_name) AS mailgroups
        FROM newsletter_items ni
        INNER JOIN newsletter_fields nf ON (nf.field_letter_uid = ni.letter_id)                    
        LEFT JOIN newsletter_item_receivers ON (newsletter_item_receivers.letter_id = ni.letter_id)
        INNER JOIN newsletter_mailgroups nm ON (FIND_IN_SET(nm.mailgroup_id, newsletter_item_receivers.value))            
        WHERE nf.field_name = 'letter_headline' AND ni.template = '". $template ."' AND deleted = 0
        GROUP BY ni.letter_id

我想要的是加入包含ifo的newsletter_clickstat中有关特定时事通讯链接的数据（例如链接点击次数）。

我试图插入

LEFT JOIN newsletter_clickstat cs ON (cs.letter_id = ni.letter_id)

但那并没有做任何事情

解决：

    SELECT ni.*, GROUP_CONCAT(DISTINCT newsletter_item_receivers.value ORDER BY newsletter_item_receivers.value) AS receivers, nf.*, GROUP_CONCAT(DISTINCT nm.mailgroup_name ORDER BY nm.mailgroup_name) AS mailgroups, cs.*
    FROM newsletter_items ni
    INNER JOIN newsletter_fields nf ON (nf.field_letter_uid = ni.letter_id)                    
    LEFT JOIN newsletter_item_receivers ON (newsletter_item_receivers.letter_id = ni.letter_id)
    INNER JOIN newsletter_mailgroups nm ON (FIND_IN_SET(nm.mailgroup_id, newsletter_item_receivers.value)) 
    LEFT JOIN newsletter_clickstat cs ON (cs.letter_id = ni.letter_id)                 
    WHERE nf.field_name = 'letter_headline' AND ni.template = '". $template ."' AND deleted = 0
    GROUP BY ni.letter_id

Answer 1

（升级到答案）

您还需要从结果集中选择newsletter_clickstat中的列...请记住您正在执行分组操作，因此需要应用聚合函数或更改列你执行你的小组。

在现有语句中添加联接

1 个答案: