Question

我正在构建一个发送电子邮件的系统，我需要进入[User]表来检索要发送的电子邮件，以及将用于取消订阅目的的GUID（uniqueidentifier类型）。

这适用于电子商务解决方案，因为匿名用户和登录用户可以拥有相同的电子邮件地址，因此会创建重复的电子邮件条目，这些条目需要在查询中有所区别。

我无法找到检索电子邮件和guid的解决方案，但只能在电子邮件中有所区别。到目前为止，这是我的查询。

SELECT Email, User_GUID
FROM [User]
WHERE 
    IsActive = 1 AND 
    IsEmailValid = 1 AND
    IsNotActiveBecauseUnsubscribed = 0 AND
    Subscribed = 1
GROUP BY Email, User_GUID

Answer 1

with cte
as
(
    select *, row_number() over (partition by Email order by User_GUID) RowNumber
    from [User]
    where 
        IsActive = 1 and 
        IsEmailValid = 1 and 
        IsNotActiveBecauseUnsubscribed = 0 and 
        Subscribed = 1
)
select Email, User_GUID
from cte
where RowNumber = 1

或

select Email, User_GUID
from
(
    select *, row_number() over (partition by Email order by User_GUID) RowNumber
    from [User]
    where 
        IsActive = 1 and 
        IsEmailValid = 1 and 
        IsNotActiveBecauseUnsubscribed = 0 and 
        Subscribed = 1
) tt
where RowNumber = 1

Answer 2

你可以做到

SELECT Distinct Email, User_GUID
FROM [User]
WHERE IsActive = 1 AND IsEmailValid = 1 And IsNotActiveBecauseUnsubscribed = 0 AND Subscribed = 1
GROUP BY Email, User_GUID

Sql Server组由多列唯一性组成，仅在一列上

2 个答案: