Export Database to File
Drupal 6 and 7
drush cc
drush sql-dump > ~/my-sql-dump-file-name.sql
drush sql-dump --gzip --result-file=backupdbsite.sql
Drupal 8
drush cr
drush sql-dump > ~/my-sql-dump-file-name.sql
drush sql-dump --gzip --result-file=backupdbsite.sql
Import Database
gzip -d my-sql-dump-file-name.sql.gz
drush sql-drop
drush sql-cli < ~/my-sql-dump-file-name.sql