Apparently long ago there was a rename database command but this was dropped for security reasons.
Now you have to do this:
for table in `mysql -u root -ppassword -s -N -e “use old_db;show tables from old_db;”`; do mysql -u root -ppassword -s -N -e “use old_db;rename table old_db.$table to new_db.$table;”; done;
Note:
Remember to create new_db first
Reference:
https://stackoverflow.com/questions/67093/how-do-i-quickly-rename-a-mysql-database-change-schema-name