Finding and Deleting Duplicate Records

October 5, 2005 with No comments

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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