用于计算重复项的SQL查询


SQL query to count duplicates

本问题已经有最佳答案，请猛点这里访问。

请协助我查询重复计数和查询以删除重复项。

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我同意所有意见，请参阅如何询问

在这个机会中，这对你有用，并且为了它对我自己来说是一个很好的练习，它帮助其他人偶然发现这个，这里有一些GENERIC代码可以做到：

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  WITH CTE AS
  (
    SELECT
    COALESCE(Col1,'') AS Col1,
    COALESCE(Col2,'') AS Col2, ROW_NUMBER() OVER(PARTITION BY col1,col2 ORDER BY col1,col2) AS row_id
    FROM MyTable
  )

DELETE CTE WHERE row_id >1;

例：

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CREATE TABLE #things (FirstName VARCHAR(10), LastName VARCHAR(10))
INSERT INTO #things (FirstName, LastName)
VALUES('thing','lastthing'),('thing','lastthing'),('otherthing', 'something')

SELECT * FROM #things

  ;WITH CTE AS
  (
    SELECT
    COALESCE(firstname,'') AS Col1,
    COALESCE(lastname,'') AS Col2, ROW_NUMBER() OVER(PARTITION BY firstname,lastname ORDER BY firstname,lastname) AS row_id
    FROM #things
  )

DELETE CTE WHERE row_id >1;

SELECT * FROM #things

DROP TABLE #things