根据特定条件从CTE中删除重复项

Question

我想根据某个条件从我的CTE中删除重复的条目，如果有2条记录具有相同的电子邮件地址，我希望只有具有refduserID的记录。应删除具有0 refdUserID的另一个重复记录。

Answer 1

理论上，你可以添加第二个CTE和一个额外的列。此额外列根据特定条件为每一行分配一个行号 - 在您的情况下，按电子邮件地址分区（例如，在考虑“重复”行时要用于比较的列），以及任意顺序，以决定你要保留哪一个（我使用了referrerid，所以最早插入的将保留）。

然后在CTE的下一个“层”中，我只选择行号为1的那些 - 例如每个“小组”的顶部。

编辑：已更新实际代码，因为OP发布了它...

CREATE PROCEDURE [dbo].[Friendreferralsbyuser]
  @userID INT
AS
    WITH INV ( referrerID, refdEmail, referringTime, referredName, refdUserID )
         AS (SELECT i.userID AS referrerID,
                    i.emailAddress AS refdEmail,
                    i.TIMESTAMP AS referringTime,
                    i.referredName,
                    0 AS refdUserID
             FROM   Invitations AS i
             WHERE  i.userID = @userID),
         INR ( referrerID, refdEmail, joiningtime, referredName, refdUserID )
         AS (SELECT i.referralID AS referrerID,
                    u.email AS refdEmail,
                    i.TIMESTAMP AS joiningtime,
                    u.userName AS referredName,
                    i.userID AS refdUserID
             FROM   InvitationReferrals AS i
                    INNER JOIN Users AS u
                            ON u.userID = i.userID
             WHERE  i.referralID = @userID),
         JOINED ( referrerID, refdEmail, times, referredName, refdUserID )
         AS (SELECT i.referrerID,
                    i.refdEmail,
                    i.referringTime,
                    i.referredName,
                    i.refdUserID
             FROM   INV AS i
             UNION
             SELECT i.referrerID,
                    i.refdEmail,
                    i.joiningtime,
                    i.referredName,
                    i.refdUserID
             FROM   INR AS i),
         ROWNUMBERS (referrerID, refdEmail, times, referredName, refdUserID, RN)
         AS (SELECT referrerID,
                    refdEmail,
                    times,
                    referredName,
                    refdUserID,
                    Row_number()
                      OVER (
                        PARTITION BY refdEmail
                        ORDER BY refdUserID DESC, referrerID))
    SELECT referrerID,
           refdEmail,
           times,
           referredName,
           refdUserID
    FROM   ROWNUMBERS
    WHERE  RN = 1

Answer 2

试试这个，

 ;With CTE as
    (
    select *, rank() over (partition by rfdEmail order by refduserID desc) as r
    from myTable
    )
    delete from CTE where r > 1

Answer 3

将此添加到我的存储过程中并且有效。

DuplicateSorting AS （

SELECT *，rank（）OVER

（PARTITION BY refdEmail ORDER BY refduserID desc）AS nn FROM JOINED），

RemovedDuplicates AS （     选择 *     FROM DuplicateSorting     在哪里rn = 1 ）

SELECT * FROM RemovedDuplicates