Use fallowing query For searching duplicate Record from table
SELECT record_feild,
COUNT(record_feild) AS Occurrences_count
FROM Record_table
GROUP BY record_feild
HAVING ( COUNT(record_feild) > 1 )
Use fallowing query deleting duplicate Record from table
delete
FROM Record_table
WHERE record_id NOT IN
(
SELECT MAX(record_id)
FROM Record_table
GROUP BY record_feild)