显示重复的所有 RowNumber 记录？

Question

我有 table 个字符串资源：

;WITH cte AS 
(
    SELECT 1 AS id , 'john' AS name, 10 AS age
    UNION   
    SELECT 2 AS id , 'john' AS name, 10 AS age
    UNION   
    SELECT 3 AS id , 'john' AS name, 12 AS age
    UNION   
    SELECT 4 AS id , 'paul' AS name, 6 AS age
    UNION   
    SELECT 5 AS id , 'paul ' AS name, 6 AS age
    UNION   
    SELECT 6 AS id , 'paul different' AS name, 7 AS age
    UNION   
    SELECT 7 AS id , 'ringo' AS name, 2 AS age

)

所以名字“john”的年龄是 10 岁。

后来，其他人（不是我） 也添加了 10 岁的“john”。

所以我想清除所有重复项。

但这不是问题所在。在删除之前，我想查看所有重复项。

所以我这样做了：

SELECT *
FROM   (
           SELECT ID,
                  name,
                  age,
                  ROW_NUMBER() OVER(PARTITION BY name, age ORDER BY id) AS rn
           FROM   cte
           
       ) a  WHERE a.rn>1
ORDER BY
       name,
       age,
       a.rn

结果：

这基本上显示了重复项。但我还想查看 rn=1 的位置，前提是当前值有更多版本。

问题

换句话说：我怎样才能增强我的查询：

仅当存在该记录的版本时才显示记录的所有个版本（所有行号，rn）

想要的结果：

ID  name    age rn
1   john    10  1
2   john    10  2
4   paul    6   1
5   paul    6   2

Sql online - demo

注意我知道我可以通过重新扫描 table 来获得相同的 name 和 age 。但是我想如果有更优雅的方法。

Answer 1

使用exists运算符查找duplicated的名称。试试这个。

;WITH cte AS 
(
    SELECT 1 AS id , 'john' AS name, 10 AS age
    UNION   
    SELECT 2 AS id , 'john' AS name, 10 AS age
    UNION   
    SELECT 3 AS id , 'john' AS name, 12 AS age
    UNION   
    SELECT 4 AS id , 'paul' AS name, 6 AS age
    UNION   
    SELECT 5 AS id , 'paul ' AS name, 6 AS age
    UNION   
    SELECT 6 AS id , 'paul different' AS name, 7 AS age
    UNION   
    SELECT 7 AS id , 'ringo' AS name, 2 AS age

)
, cte1
         AS (SELECT ID,
                    name,
                    age,
                    Row_number() OVER(PARTITION BY name, age ORDER BY id) AS rn
             FROM   cte)
    SELECT *
    FROM   cte1 a
    WHERE  EXISTS (SELECT 1
                   FROM   cte1 b
                   WHERE  a.name = b.name and a.age=b.age
                          AND b.rn > 1)
    ORDER  BY name, age, a.rn

或使用Inner Join

    SELECT a.id,a.name,a.age
    FROM   cte1 a
           JOIN cte1 b
             ON a.name = b.name
                AND a.age = b.age
                AND b.rn > 1
    ORDER  BY a.name, a.age, a.rn

或者要在单次 table 扫描中使用 Dense_Rank 加上 window function

    ;WITH cte AS 
    (
        SELECT 1 AS id , 'john' AS name, 10 AS age
        UNION   
        SELECT 2 AS id , 'john' AS name, 10 AS age
        UNION   
        SELECT 3 AS id , 'john' AS name, 12 AS age
        UNION   
        SELECT 4 AS id , 'paul' AS name, 6 AS age
        UNION   
        SELECT 5 AS id , 'paul ' AS name, 6 AS age
        UNION   
        SELECT 6 AS id , 'paul different' AS name, 7 AS age
        UNION   
        SELECT 7 AS id , 'ringo' AS name, 2 AS age

    )
    , cte1
             AS (SELECT ID,
                        name,
                        age,
                        count(age) over (partition by name,age) cnt,
                        dense_rank() OVER(PARTITION BY name ORDER BY age) AS rn
                 FROM   cte)
                 SELECT *
                 FROM   cte1
                 WHERE  rn = 1
                        AND cnt > 1

显示重复的所有 RowNumber 记录？

Show all RowNumber records for duplicates?

sql-server

sql-server-2008-r2