Yes, Omniscope will import the results of any valid SQL statement that returns a table. The ODBC protocol is currently limited to connecting to only a single database. If you need to connect to/join tables from more than one database for import and refresh, you must use the JDBC protocol. In general, JDBC will out-perform ODBC.
For more information on importing your data, see the User Guide sections on Using your Data and Connecting to Databases. For more technical articles, see the KnowledgeBase sections on Importing Data Files and Database Connections.