Dropping a database deletes all tables and data from disk, including the transaction log that records alterations to the database. It also drops all of the dbspaces associated with the database.
DROP DATABASE dbname
You must specify the database name and its path name exactly as they were specified when the database was created.
DROP DATABASE 'c:\sybase\data\mydb.db'
The database must be stopped before you can drop it. If the connection parameter AUTOSTOP=no is used, you may need to issue a STOP DATABASE statement.