MSSQL查詢刪除從一個表的重複行留下不同的行表

Question

我需要從具有相同customer_id和deactivation_date一個表Log刪除除類似的行的第一次出現所有重複行。我如何用最少數量的sql語句實現這一目標。

我正在使用MS SQL Server 2008 express版本。

Answer 1

喜歡的東西：

DELETE FROM Log WHERE LogId NOT IN 
(SELECT Min(LogId) FROM Log GROUP BY customer_id, deactivation_date) 

Answer 2

你沒有給我們太多的工作。但是，也許是這樣的：

;WITH CTE 
AS 
(
    SELECT 
     ROW_NUMBER() OVER(PARTITION BY [Log].customer_id ORDER BY 
           deactivation_date) AS RowNbr, 
     [Log].* 
    FROM 
     [Log] 
) 
DELETE FROM [Log] 
WHERE EXISTS 
    (
     SELECT 
      NULL 
     FROM 
      CTE 
     WHERE 
      CTE.RowNbr>1 
      AND CTE.log_id =[Log].log_id 
    ) 

Answer 3

或者：

with cte as (
    select row_number() over (partition by customer_id, deactivation_date 
    order by log_id) as rn 
    from Log) 
delete from cte 
    where rn > 1;