You can access a list of the field names out of a prepared SELECT statement, by using $sth->{NAME}, which returns an array reference — you can turn it into an array/list using @{$sth->{NAME}}. If you want them all converted to uppercase or lowercase, use $sth->{NAME_uc} or $sth->{NAME_lc}.

Perhaps you want something else. Perhaps you want a complete description of all tables in a database. You don't say. There are ways, yes, but they're generally very driver (red: "DBD") specific. I'm not familiar enough with DBD::ODBC to know the specifics for this driver. I could check if you're really interested.