问使用添加的唯一约束删除列中的重复值

EN

UPDATE "User"
    SET "displayName" = NULL
    WHERE id > (SELECT MIN(u2.id)
                FROM "User" u2
                WHERE u2."displayName" = u."displayName"
               );

WITH X AS 
(
SELECT id
     , [displayName] 
     , ROW_NUMBER() OVER (partition BY [displayName] ORDER BY id) AS rnum
FROM [User]
)
UPDATE X 
 SET [displayName] = NULL
WHERE rnum > 1 

UPDATE X
 SET [displayName] = NULL 
FROM (
        SELECT id
             , [displayName] 
             , ROW_NUMBER() OVER (partition BY [displayName] ORDER BY id) AS rnum
        FROM [User]
     ) x
WHERE rnum > 1