it is possible to recover your data if the database is in full revovery model. You have to perform
1. a transaction log backup
2. restore the most recent full backup with norecovery
3. restore all (if exist) transaction log backups with norecovery
4. restore the last transaction log with recovery using the STOPAT option if you know the exact time that the wrong query has been fired.
If the database is in simple recovery model it is not possible to recover your data.