Jan Ole Peek » SQL Tips http://www.janolepeek.com Ramblings of an Internet Hermit Thu, 11 Feb 2010 19:45:23 +0000 en hourly 1 http://wordpress.org/?v=3.0 Finding and Deleting Duplicate Records http://www.janolepeek.com/finding-and-deleting-duplicate-records-2 http://www.janolepeek.com/finding-and-deleting-duplicate-records-2#comments Wed, 05 Oct 2005 16:33:11 +0000 jopeek http://www.jpeek.net/wordpress/?p=66 1 SELECT col1, col2, col3=count(*) INTO holdkey FROM t1 GROUP BY col1, col2 HAVING count(*) > 1 DELETE t1 FROM t1, holdkey WHERE t1.col1 = holdkey.col1 AND t1.col2 = holdkey.col2 INSERT t1 SELECT [...]]]> INF: How to Remove Duplicate Rows From a Table
SELECT col1, col2, count(*)
FROM t1
GROUP BY col1, col2
HAVING count(*) > 1

SELECT col1, col2, col3=count(*)
INTO holdkey
FROM t1
GROUP BY col1, col2
HAVING count(*) > 1

DELETE t1
FROM t1, holdkey
WHERE t1.col1 = holdkey.col1
AND t1.col2 = holdkey.col2

INSERT t1 SELECT * FROM holdkeySQL

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