ORA-00911: invalid character
Remove ; (semi-colon) from the end of SQL string
In case other people wind up here looking for how to include multiple statements in a single command, you need to wrap your statements within begin and end. This will stop the invalid character errors due to the semi-colons. For example:
var command = new OracleCommand(@"
begin
select * from test;
select * from test2;
end;")