BINTOHEX causing error "attribute type is invalid"

Hi Colleagues,

  Just noticed one interesting thing. Calling bintohex in sql query ends up with error "attribute type is invalid".

CREATE COLUMN TABLE A_COLUMN(

PK INTEGER PRIMARY KEY,

F9 BLOB DEFAULT NULL

);

SELECT   BINTOHEX("F9") FROM A_COLUMN;

   However it works fine for row table.

CREATE ROW TABLE A_ROW(

PK INTEGER PRIMARY KEY,

F9 BLOB DEFAULT NULL

);

SELECT   BINTOHEX("F9") FROM A_ROW;

   Is it a bug or I am not using it correctly?

Thanks,

Yang