唯一单击次数（SQL查询）

我的服务中有一个电子邮件发送系统（针对我的电子邮件订户）。我需要获得有关发送邮件、点击次数和电子邮件打开次数的统计信息。所有信息存储在PostgreSQL数据库中

我有一个包含订户列表的表（

subscriber\u collections

）：

因此，我有一个表，用于存储每个订户列表的电子邮件（

电子邮件

，一对多关系）

此外，我还有一个表

mail\u activities

，其中存储了有关不同电子邮件活动（如单击、打开、发送等）的信息：

请注意，用户可以重复单击（或打开）同一封电子邮件，信息将保存在数据库中

我有一个SQL查询，它获取每个电子邮件和订阅者集合的不同活动数：

SELECT
    MA.message_id
    ,MA.message_subject
    ,SC.name as subscriber_collection_name
    ,MA.date AS activity_date
    ,SUM(CASE WHEN MA.type='Sends' THEN 1 ELSE 0 END) as sends_count
    ,SUM(CASE WHEN MA.type='Opens' THEN 1 ELSE 0 END) as opens_count
    ,SUM(CASE WHEN MA.type='Clicks' THEN 1 ELSE 0 END) as clicks_count
FROM
    mail_activities MA
    INNER JOIN emails E ON MA.email_address = E.email_address
    INNER JOIN subscriber_collections SC ON E.subscriber_collection_id = SC._id

GROUP BY
    MA.message_id
    ,MA.message_subject
    ,SC._id
    ,SC.name
    ,MA.date                    
ORDER BY
    message_id

这个查询工作正常。以下是此数据的结果：

问题：我需要获得每个

电子邮件地址的独特点击次数并打开活动。我需要在该查询中以附加列的形式获取此信息（
unique\u单击
，然后
unique\u打开
）。例如，两次点击字母
Hello msg按用户
jay10@email.com
表中的电子邮件应视为一封。如何在其他列中获取此信息？谢谢

p.S:对不起，我的英语不好……
如果我理解正确，您可以使用条件计数（不重复）
：

不过，我不太确定这是否适合您现有的查询。您希望每封电子邮件具有唯一的计数（从描述中可以看出），但您是通过
message\u id
进行聚合的

嗯。也许您需要不同的电子邮件地址：

COUNT(DISTINCT CASE WHEN MA.type = 'Sends' THEN ma.email_address END) as sends_unique_count
COUNT(DISTINCT CASE WHEN MA.type = 'Opens' THEN ma.email_address END) as opens_unique_count
COUNT(DISTINCT CASE WHEN MA.type = 'Clicks' THEN ma.email_address END) as clicks_unique_count

_id  message_id  message_subject  activity_date   email_address       type
============================================================================
 1      25           Hello msg!    2017-11-21   john.smith@email.com  Sends
 2      25           Hello msg!    2017-11-21   john.smith@email.com  Opens
 3      25           Hello msg!    2017-11-21   john.smith@email.com  Clicks
 4      25           Hello msg!    2017-11-21   jay10@email.com       Clicks
 5      25           Hello msg!    2017-11-21   jay10@email.com       Clicks
 6      16           Discount!     2017-11-21   second@email.com      Opens
 7      16           Discount!     2017-11-21   second@email.com      Opens
 8      16           Discount!     2017-11-21   james3@email.com      Opens

SELECT
    MA.message_id
    ,MA.message_subject
    ,SC.name as subscriber_collection_name
    ,MA.date AS activity_date
    ,SUM(CASE WHEN MA.type='Sends' THEN 1 ELSE 0 END) as sends_count
    ,SUM(CASE WHEN MA.type='Opens' THEN 1 ELSE 0 END) as opens_count
    ,SUM(CASE WHEN MA.type='Clicks' THEN 1 ELSE 0 END) as clicks_count
FROM
    mail_activities MA
    INNER JOIN emails E ON MA.email_address = E.email_address
    INNER JOIN subscriber_collections SC ON E.subscriber_collection_id = SC._id

GROUP BY
    MA.message_id
    ,MA.message_subject
    ,SC._id
    ,SC.name
    ,MA.date                    
ORDER BY
    message_id

COUNT(DISTINCT CASE WHEN MA.type = 'Sends' THEN ma.message_id END) as sends_unique_count
COUNT(DISTINCT CASE WHEN MA.type = 'Opens' THEN ma.message_id END) as opens_unique_count
COUNT(DISTINCT CASE WHEN MA.type = 'Clicks' THEN ma.message_id END) as clicks_unique_count

COUNT(DISTINCT CASE WHEN MA.type = 'Sends' THEN ma.email_address END) as sends_unique_count
COUNT(DISTINCT CASE WHEN MA.type = 'Opens' THEN ma.email_address END) as opens_unique_count
COUNT(DISTINCT CASE WHEN MA.type = 'Clicks' THEN ma.email_address END) as clicks_unique_count