--------------
SELECT version()
--------------

+-------------------------+
| version()               |
+-------------------------+
| 5.0.45-community-nt-log | 
+-------------------------+
1 row in set (0.00 sec)

--------------
DELETE FROM PUBACC_FR
  WHERE convert( PUBACC_FR.frequency_assigned, DECIMAL ) >= 1000
--------------

Query OK, 290789 rows affected (2 min 23.19 sec)

Bye