MySql remove duplicate on composite 2 or more columns

I've been write SQL to remove duplicate rows in PostgreSQL and many other trick with huge DB.

Now I try with MySQL.

Find all duplicate rows by composite columns, ie. user_id and file_date. Both is integer: file_date in unix_timestamp.

select   id,
 user_id,
         file_date,
         count(*)
from     detailed_claims
group by user_id,
         file_date
having   count(*) > 1

We just need id column to remove, so only select id:

select id from (select id, user_id, file_date, count(*) from detailed_claims group by user_id, file_date having count(*) > 1 ) as blondie

Result:
|id          |
|  46400 |
|  46421 |
|  46402 |
|  46159 |
|  46414 |
|  46157 |
|  46161 |
|  46163 |
|  46405 |
|  46164 |
|  46165 |
|  46166 |
|  46158 |
|  46167 |
|  46162 |
|  46406 |
|  46417 |
|  46177 |
+--------+
4885 rows in set (1.14 sec)

Now remove:

delete from detailed_claims where id in (select id from (select   id,
    user_id,
         file_date,
         count(*)
from     detailed_claims
group by user_id,
         file_date
having   count(*) > 1
                ) as blondie
)


OK, now we can add Unique indexes to 2 columns user_id and file_date without error msg.