You need to write one function -- something like "blobtochar" in the following:

ops$tkyte@8i> create table demo
2 ( id int primary key,
3 theBlob bfile
4 )
5 /

Table created.

ops$tkyte@8i>
ops$tkyte@8i> create or replace directory
2 my_files as '/export/home/tkyte/public_html';

Directory created.

ops$tkyte@8i>
ops$tkyte@8i> insert into demo
2 values
3 ( 1, bfilename( 'MY_FILES', 'blob.sql' ) );

1 row created.

ops$tkyte@8i>
ops$tkyte@8i>
ops$tkyte@8i> create or replace
2 function blobtochar( p_blob in bfile ) return varchar2
3 as
4 l_raw raw(4000);
5 l_bfile bfile default p_blob;
6 begin
7 dbms_lob.fileopen( l_bfile );
8 l_raw := dbms_lob.substr( l_bfile,4000,1 );
9 dbms_lob.fileclose( l_bfile );
10 return utl_raw.cast_to_varchar2(l_raw);
11 end;
12 /

Function created.

ops$tkyte@8i>
ops$tkyte@8i> column x format a40 word_wrapped
ops$tkyte@8i> select id, blobtochar(theBlob) x from demo
2 /

ID X
---------- ----------------------------------------
1 drop table demo;
create table demo
( id int primary key,
theBlob bfile
)
/
create or replace directory
my_files as
'/export/home/tkyte/public_html';
insert into demo
values
( 1, bfilename( 'MY_FILES', 'blob.sql' )
);
create or replace
function blobtochar( p_blob in bfile )
return varchar2
as
l_raw raw(4000);
l_bfile bfile default p_blob;
begin
dbms_lob.fileopen( l_bfile );
l_raw := dbms_lob.substr( l_bfile,4000,1
);
dbms_lob.fileclose( l_bfile );
return utl_raw.cast_to_varchar2(l_raw);
end;
/
column x format a40 word_wrapped
select id, blobtochar(theBlob) x from
demo
/