Youngjoo Song wrote:
>
> Hello,
>
> I'm trying to find duplicate records in a table and extract them into
> another table. Anybody has a logic for finding duplicates? A detailed select
> statement would be appreciated, if that's possible. Thanks.
>
> -- YJ
>
Suppose we have table foo(n int, m int) and some pair of (n,m) are
identical. To find them:
SELECT t1.n,t1.m, count(*) as c FROM foo as t1, foo as t2
WHERE
t1.m = t2.m AND t1.n = t2.n GROUP BY t1.m, t1.n HAVING c > 1;
This is actually tested. c contains the square of the number duplicate
rows.
--
Sasha Pachev
http://www.sashanet.com/ (home)
http://www.direct1.com/ (work)
