Well lookee here ... http://asktom.oracle.com/pls/ask/f?p...15151793634161

Tom Kyte likes the exception trapping method as well.

I like his "if ( sqlcode = 12000 ) then" syntax also, but I'd comment it, like ...
[code]
begin
execute immediate 'drop materialized view log on xyz';
exception
when others
if ( sqlcode = 12000 ) then null; -- suppress "Table has no MV log" error
else raise;
end if;
end;
/