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I have written a query to remove duplicate records from a table
;WITH a as
(
SELECT Firstname,ROW_NUMBER() OVER(PARTITION by Firstname, empID ORDER BY Firstname)
AS duplicateRecCount
FROM dbo.tblEmployee
)
--Now Delete Duplicate Records
DELETE FROM tblEmployee
WHERE duplicateRecCount > 1
But I don't know where I went wrong it is saying
Invalid column name
duplicateRecCount
Can someone help me?
223
1) First identify the rows those satisfy the definition of duplicate and insert them into temp table, say #tableAll . 2) Select non-duplicate(single-rows) or distinct rows into temp table say #tableUnique. 3) Delete from source table joining #tableAll to delete the duplicates.
To remove duplicates, use the drop_duplicates() method.
How to Eliminate Duplicate Values Based on Only One Column of the Table in SQL? In SQL, some rows contain duplicate entries in a column. For deleting such rows, we need to use the DELETE keyword along with self-joining the table with itself.
You need to reference the CTE in the delete statement...
WITH a as
(
SELECT Firstname,ROW_NUMBER() OVER(PARTITION by Firstname, empID ORDER BY Firstname)
AS duplicateRecCount
FROM dbo.tblEmployee
)
--Now Delete Duplicate Records
DELETE FROM a
WHERE duplicateRecCount > 1
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