First and Last data

from the below table I need the Last_data and last_data from 6 month. with different DB_name so my output would look like : DB_name backup_start Backup_finish Stock_any 8/1/2016 8/1/2016 Stock_any 1/1/2017 1/1/2017 Bond 8/1/2016 8/1/2016 Bond 1/1/2