If you want to keep the row with the lowest id
value:
DELETE FROM NAMES
WHERE id NOT IN (SELECT *
FROM (SELECT MIN(n.id)
FROM NAMES n
GROUP BY n.name) x)
If you want the id
value that is the highest:
DELETE FROM NAMES
WHERE id NOT IN (SELECT *
FROM (SELECT MAX(n.id)
FROM NAMES n
GROUP BY n.name) x)
The subquery in a subquery is necessary for MySQL, or you'll get a 1093 error.