Hellp needed urgent in modifying the query

Question

my requriment is as follows.
the data looks like as follows - 3 columns
sheet_id sequence_no rap_no
1 2
1 4
1 5
1 1
2 4
2 6
2 7
3 8
3 10
4 3
4 7
and the max of seqno should be updated on rap_no.
is the group by clause not neededin the following query .
In tht case how to modify the foll query.
     update t3756_cue_sheet_music a set a.c3756_rap_sequence_no=
(select max(to_number(c3756_sequence_no))
FROM t3756_cue_sheet_music b
where a.c3756_cue_sheet_id = b.c3756_cue_sheet_id)
WHERE c3756_rap_sequence_no is NULL;
Thanks in advance.
Do reply

Answer 1

Can you be a little more clear?
create table t
(sheet_id number
,sequence_no number
,rap_no number);
alter table t add constraint tpk primary key (sheet_id, sequence_no);
insert into t (sheet_id, sequence_no) values (1, 2);
insert into t (sheet_id, sequence_no) values (1, 4);
insert into t (sheet_id, sequence_no) values (1, 5);
insert into t (sheet_id, sequence_no) values (1, 1);
insert into t (sheet_id, sequence_no) values (2, 4);
insert into t (sheet_id, sequence_no) values (2, 6);
insert into t (sheet_id, sequence_no) values (2, 7);
insert into t (sheet_id, sequence_no) values (3, 8);
insert into t (sheet_id, sequence_no) values (3, 10);
insert into t (sheet_id, sequence_no) values (4, 3);
insert into t (sheet_id, sequence_no) values (4, 7);
update t a
set a.rap_no=
(select max(to_number(sequence_no))
FROM t b
where a.sheet_id = b.sheet_id)
WHERE rap_no is NULL;
select *
  from t;
SHEET_ID SEQUENCE_NO         RAP_NO
         1           2          5
         1           4          5
         1           5          5
         1           1          5
         2           4          7
         2           6          7
         2           7          7
         3           8         10
         3          10         10
         4           3          7
         4           7          7Doesn't this give you the correct results?