Doppelte Datensätze in der MySQL-DB finden:
SELECT *
FROM my_table
WHERE my_column IN (
SELECT my_column
FROM my_table
GROUP BY my_column
HAVING count(my_column) > 1
)
ORDER BY my_column
Doppelte Datensätze löschen:
DELETE
FROM my_table
WHERE my_column IN (
SELECT my_column
FROM my_table
GROUP BY my_column
HAVING count(my_column) > 1
)
ORDER BY my_column