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deleting duplicates in a sql table

Posted on 2016-09-26
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Last Modified: 2016-09-28
I have 7 columns.
i need rows to be deleted if there is a duplicate if all cells match between two rows on all 7 values.
is there an easy to do this?
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Question by:jamesmetcalf74
  • 2
4 Comments
 
LVL 35

Expert Comment

by:YZlat
ID: 41816877
you could do the following:

1) Select all distinct rows into a new table
2) truncate your original table
3) copy rows from the table you created into the original table

SELECT DISTINCT col1,col2,col3
INTO   #staging
FROM   Table1

TRUNCATE TABLE Table1

INSERT INTO Table1 (col1,col2,col3)
SELECT col1,col2,col3
FROM #staging

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LVL 35

Expert Comment

by:YZlat
ID: 41816884
you could also create a new regular table with the same structure, insert distinct data in that table, then delete your original table and rename new table to the same name as original table had
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LVL 34

Accepted Solution

by:
Brian Crowe earned 250 total points
ID: 41816911
WITH cteDistinct AS
(
	SELECT Col1, Col2, Col3, Col4, Col5, Col6, Col7,
		ROW_NUMBER() OVER(PARTITION BY Col1, Col2, Col3, Col4, Col5, Col6, Col7) AS RowNumber
	FROM myTable
)
DELETE cteDistinct
WHERE RowNumber > 1

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1
 
LVL 28

Assisted Solution

by:Pawan Kumar
Pawan Kumar earned 250 total points
ID: 41817149
Modified Brian Version  (Removed syntax errors)

--

WITH cteDistinct AS
(
	SELECT Col1, Col2, Col3, Col4, Col5, Col6, Col7,
		ROW_NUMBER() OVER(PARTITION BY Col1, Col2, Col3, Col4, Col5, Col6, Col7 ORDER BY (SELECT 1)) AS RowNumber
	FROM myTable
)
DELETE FROM cteDistinct
WHERE RowNumber > 1

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