mysql encuentra duplicados en la misma mesa
## Find ALL duplicate recods by value (without grouping them by value) ##
# to find the duplicate,
# replace all instances of tableName with your table name
# and all instances of duplicateField with the field name where you look for duplicates
SELECT t1.*
FROM tableName AS t1
INNER JOIN(
SELECT duplicateField
FROM tableName
GROUP BY duplicateField
HAVING COUNT(duplicateField) > 1
)temp ON t1.duplicateField = temp.duplicateField
order by duplicateField
Yoshkinawa