SQL Server 2008-使用ROW_NUMBER查找重復項

Question

我有以下SQL可以查找重復項

SELECT  *
FROM (SELECT
      id,
      ShipAddress,
      ShipZIPPostal,
      ROW_NUMBER() OVER (PARTITION BY shipaddress, shipzippostal ORDER BY shipaddress) ROWNUM
FROM orders
WHERE CONVERT(date, orderdate) = CONVERT(date, GETDATE())) x
WHERE rownum > 1

我只想查看行，如果Rownum的值> 1，那么我想查看其對應的行，其中rownum = 1。

所以基本上，如果一行中有重復項，我想查看原始行及其所有重復項。

如果一行沒有重復，那么我不想看到它（它將具有rownum = 1）

請問我該怎么辦？

干杯

Answer 1

使用count(*)而不是row_number() ：

SELECT *
FROM (SELECT id, ShipAddress, ShipZIPPostal,
             COUNT(*) OVER (PARTITION BY shipaddress, shipzippostal) as cnt
      FROM orders
      WHERE CONVERT(date, orderdate) = CONVERT(date, GETDATE())
     ) x
WHERE cnt > 1;

Answer 2

除了戈登的答案之外，如果您出於某些學術原因想要保留row_number（）方法，則可以執行以下操作：

SELECT  *
FROM (SELECT
      id,
      ShipAddress,
      ShipZIPPostal,
      ROW_NUMBER() OVER (PARTITION BY shipaddress, shipzippostal ORDER BY shipaddress) ROWNUM
FROM orders
WHERE CONVERT(date, orderdate) = CONVERT(date, GETDATE())) x
WHERE EXISTS(
 SELECT * FROM x x2
 WHERE x.shipaddress=x2.shipaddress
 AND x.shipzippostal=x2.shipzippostal
 AND x2.ROWNUM>1
)

我個人實際上更喜歡這樣的CTE結構：

WITH cte AS (
  SELECT
      id,
      ShipAddress,
      ShipZIPPostal,
      ROW_NUMBER() OVER (PARTITION BY shipaddress, shipzippostal ORDER BY shipaddress) ROWNUM
  FROM orders
  WHERE CONVERT(date, orderdate) = CONVERT(date, GETDATE())
) 
SELECT  *
FROM cte
WHERE EXISTS(
 SELECT * FROM cte x2
 WHERE cte.shipaddress=x2.shipaddress
 AND cte.shipzippostal=x2.shipzippostal
 AND x2.ROWNUM>1
)

Answer 3

您可以添加第二個row_number，但是將順序更改為ID，以使其有所不同，然后比較2個row_numbers

SELECT
    *
FROM
    (SELECT
        id,
        ShipAddress,
        ShipZIPPostal,
        ROW_NUMBER() OVER (PARTITION BY shipaddress,shipzippostal ORDER BY id) ROWNUM1,
        ROW_NUMBER() OVER (PARTITION BY shipaddress,shipzippostal ORDER BY id DESC) ROWNUM2
     FROM
        orders
     WHERE
        CONVERT(DATE,orderdate) = CONVERT(DATE,GETDATE())
    ) x
WHERE
    ROWNUM1 <> ROWNUM2