Search notes:

ORA-00998: must name this expression with a column alias

The following create view statement throws ORA-00998: must name this expression with a column alias:
create view ora_00998_test
as
   select length('foo')
from
   dual;
Better:
create view ora_00998_test
as
   select length('foo') length_foo
from
   dual;

See also

Columns

Index