GroupBy（MS SQL Server 与 MySQL）

Question

我和这个人有类似的问题： GROUP BY (MySQL vs SQL server)

SELECT 
    SubscriberKey,
    EmailAddress,
    MIN(CreatedDate) AS CreateDate,
FROM [_ListSubscribers]
WHERE EmailAddress = 'email@address.com'
AND STATUS = 'active'
GROUP BY EmailAddress

我如何查看与记录最早的电子邮件地址相关联的 SubscriberKey 是什么？ SubscriberKey 是一个 TEXT 字段。我尝试使用 MIN(SubscriberKey) 但它没有返回正确的值。并且在 GroupBy 子句中添加它也无法返回正确的值。

这是我想要的结果：

SubscriberKey	EmailAddress	CreateDate
email@address.com	email@address.com	August 21, 2018

这是此电子邮件记录的完整数据库示例：

SubscriberKey	EmailAddress	CreateDate	Status
email@address.com	email@address.com	August 21, 2018	active
Jadfsok134324	email@address.com	May 15, 2020	active

Answer 1

在这两个数据库中，您将使用相关子查询或row_number()：

SELECT l.*
FROM (SELECT l.*,
             ROW_NUMBER() OVER (PARTITION BY emailaddress ORDER BY CreatedDate DESC) as seqnum
      FROM [_ListSubscribers] l
      WHERE EmailAddress = 'email@address.com' AND STATUS = 'active'
     ) l
WHERE seqnum = 1;

当然，如果你只想要一行，那么fetch first 在任一数据库中都更容易：

SELECT l.*
FROM [_ListSubscribers] l
WHERE EmailAddress = 'email@address.com' AND STATUS = 'active'
ORDER BY createdAt ASC
OFFSET 0 ROW FETCH FIRST 1 ROW ONLY;