SQL 按结果分组 - Salesforce Marketing Cloud

Question

我要查找所有重复记录，然后 select 所有重复项减去每组中最旧的记录，这样我就可以删除重复项并保留一个唯一记录。

当我运行这个查询时，我得到了我想要的结果。给我一个唯一的电子邮件地址和最早的创建日期。

SELECT 
    EmailAddress,
    MIN(CreatedDate)
FROM [_ListSubscribers]
WHERE EmailAddress IN
    (
        SELECT EmailAddress
        FROM _ListSubscribers
        GROUP BY EmailAddress
        HAVING COUNT(EmailAddress) > 1
    )
GROUP BY EmailAddress

当我将 SubscriberKey 添加到查询时，结果翻了一番！这是为什么？ 我只想查看与我发现的 EmailAddress 关联的 SubscriberKey，它在子查询中具有最早的日期。

SELECT 
    EmailAddress,
    SubscriberKey,
    MIN(CreatedDate)
FROM [_ListSubscribers]
WHERE EmailAddress IN
    (
        SELECT EmailAddress
        FROM _ListSubscribers
        GROUP BY EmailAddress
        HAVING COUNT(EmailAddress) > 1
    )
GROUP BY EmailAddress, SubscriberKey

Answer 1

您获得了多条记录，因为您按 SubscriberKey 分组。您需要按 EmailAddress 和 CreatedDate 进行匹配。尝试做一个子查询并将其连接回原来的 table.

select 
[_ListSubscribers].EmailAddress,
[_ListSubscribers].SubscriberKey,
[_ListSubscribers].CreatedDate,
from
(
SELECT 
    EmailAddress,
    MIN(CreatedDate) as CreatedDate
    FROM [_ListSubscribers]
    GROUP BY EmailAddress, SubscriberKey
    Having count(EmailAddress)>1
) SubTbl
inner join
[_ListSubscribers] on
[_ListSubscribers].EmailAddress = SubTbl.EmailAddress
and
[_ListSubscribers].CreatedDate = SubTbl.CreatedDate

Answer 2

I'm looking to find all duplicate records and then select all duplicates minus the oldest record from each set so that I can delete duplicates and keep one unique record.

使用ROW_NUMBER():

select l.*
from (select l.*,
             row_number() over (partition by EmailAddress order by CreatedDate desc) as seqnum
      from _ListSubscribers l
     ) l
where seqnum > 1;

但是，如果你想删除除最新记录以外的所有记录，你可以使用：

delete from _ListSubscribers
    where CreatedDate < (select max(CreatedDate)
                         from _ListSubscribers l2
                         where l2.EmailAddress = _ListSubscribers.EmailAddress
                        );

如果您想要最早的记录，您可以使用 min() 而不是 max() 翻转逻辑。

SQL 按结果分组 - Salesforce Marketing Cloud

SQL GROUP BY Results - Salesforce Marketing Cloud

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