Netezza ODBC connection - equivalent of "use database"

Prior to Version 7.0 there wasn't an equivalent to USE. You had to log in to specific databases on the server however you can still access any object using. database.schema.objectname

Post Version 7.0 the equivalent is Set Catalog

SET CATALOG <database_name> 

Regarding your specific inquiry. Please consider using _V_TABLE_XDB instead of _V_TABLE. This system table should provide you with a list of all tables, not just those in the database you are connected to.

If you're using NPS v7.0+, then the SET CATALOG command will connect you to a different database dynamically (without having to disconnect and reconnect). The beauty of this command is that it can be submitted from an ODBC/JDBC client as well as in an nzsql script.

In Netezza you can to other database with following command -

nzsql -u <username> -pw <password> -db <databasename> -host <netezza server IP>

hope this will help you.