MySQL: find likely duplicates. SELECT first, then DELETE for safety. Alternatively, delete directly.

mysql_find_duplicates

# Delete directly:
# -------------------------------------

DELETE
n1
FROM
`tableName` n1, `tableName` n2
WHERE
n1.id = n2.id AND
n1.lastmodifieddate = n2.lastmodifieddate AND 
n1.name = n2.name AND 
n1.uid > n2.uid AND 
n1.uid <> n2.uid


# Select first (recommended):
# -------------------------------------

SELECT
n1.uid
FROM
`tableName` n1, `tableName` n2
WHERE
n1.id = n2.id AND
n1.lastmodifieddate = n2.lastmodifieddate AND 
n1.name = n2.name AND 
n1.uid > n2.uid AND 
n1.uid <> n2.uid

# ---------
# And then this:

DELETE 
FROM
`tableName`
WHERE
uid IN ()

"uid" in this case is the actual unique index within the table. "id" is an id that could be duplicated for various reasons.