Máte na mysli něco takového:
SELECT a.*, b.Count
FROM table_name AS a
INNER JOIN (
SELECT Column1, Column2, Column3, Count(*) as Count FROM table_name
GROUP BY Column1, Column2, Column3
HAVING Count > '2'
) b
ON a.Column1 = b.Column1 AND a.Column2 = b.Column2 AND a.Column3 = b.Column3
To je v podstatě to, co jste popsali ve své otázce, ale v JOIN
.