You want to dump all databases with names that start with "db".
Which command will achieve this?
mysqlpump --include-tables=db.% --result-file=all_db_backup.sql
mysqlpump > all_db_backup.sql
mysqlpump --include-databases=db --result-file=all_db_backup.sql
mysqlpump --include-databases=db% --result-file=all_db_backup.sql
Submit