Need help in sql update table

Question

Hi,
I have a data in the table like below
Before:
ID     SEQ_ID     Manager_id     Reg_days
1     1     111     1
1     2     222     3
1     3     333     5
1     4     444     7
1     5     555     9
Action: User deletes SEQ_ID #3
After:
ID     SEQ_ID     Manager_id     Reg_days
1     1     111     1
1     2     222     3
1     3     444     7
1     4     555     9
could you please help me the query to update the table how what was seq_id #4 becomes seq_id #3 and what was seq_id #5 becomes seq_id #4; i.e. every sequence number > the one deleted is decremented by one so that the sequence numbers remain contiguous.
Thx in advance

Answer 1

[Edit: why do you never mark any of your questions as "answered"? Providing feedback is a courtesy that encourages people to answer.]
user586 wrote:
Is it possible to update it to write in a procedure or trigger to call the procedure in the code. Plz. let me know or help me.I thought you said you wanted to do this every 3 or 6 months? In that case no trigger!
Do not try to do this in a trigger!
Test data:drop table T;
create table T(id, SEQ_ID, MANAGER_ID, REG_DAYS) as
with IDS as (
  select level id from DUAL connect by level <= 10
), REST as (
  select level seq_ID, level+100 MANAGER_ID, level*2 - 1 REG_DAYS
  from DUAL
  connect by level <= 10
select * from IDS, REST;
delete from T where SEQ_ID = 3;
commit;
select * from T where id = 1;
ID SEQ_ID MANAGER_ID REG_DAYS
1      1        101        1
1      2        102        3
1      4        104        7
1      5        105        9
1      6        106       11
1      7        107       13
1      8        108       15
1      9        109       17
1     10        110       19Solution:merge into T
using (
  select new_seq_id, rid from (
    select SEQ_ID,
    ROW_NUMBER() over(partition by id order by SEQ_ID) NEW_SEQ_ID,
    rowid RID
    from T
  where NEW_SEQ_ID != SEQ_ID
) NEW_T
on (T.rowid = NEW_T.RID)
when matched then update set seq_id = new_t.new_seq_id;
70 rows merged.
select * from T where id = 1;
ID SEQ_ID MANAGER_ID REG_DAYS
1      1        101        1
1      2        102        3
1      3        104        7
1      4        105        9
1      5        106       11
1      6        107       13
1      7        108       15
1      8        109       17
1      9        110       19Most importantly, if you run the MERGE twice in a row, the second time you get "0 rows merged." The code only changes the rows that need to be changed.
Edited by: Stew Ashton on Oct 29, 2012 9:15 AM