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Question

Hi ,
i ahve a table mat1 which has values
GRN_N     GRN_D     SEQ_N
1     1/1/2001 12:00:00.000 AM     [NULL]
1     1/1/2002 12:00:00.000 AM     [NULL]
1     1/1/2003 12:00:00.000 AM     [NULL]
1     1/1/2004 12:00:00.000 AM     [NULL]
2     1/1/2001 12:00:00.000 AM     [NULL]
2     1/1/2002 12:00:00.000 AM     [NULL]
2     1/1/2003 12:00:00.000 AM     [NULL]
2     1/1/2004 12:00:00.000 AM     [NULL]
I need to write a logic to update the seq_n so that the output is
1     1/1/2001 12:00:00.000 AM     1
1     1/1/2002 12:00:00.000 AM     2
1     1/1/2003 12:00:00.000 AM     3
1     1/1/2004 12:00:00.000 AM     4
2     1/1/2001 12:00:00.000 AM     1
2     1/1/2002 12:00:00.000 AM     2
2     1/1/2003 12:00:00.000 AM     3
2     1/1/2004 12:00:00.000 AM     4
the date will be different for each grn_n
if 4 dates are there for a grn_n then the min of the date should have 1 and max should have 4.
is it possible with a single select statement..
plz help..
thanks in advance..
mathew

Answer 1

SQL> create table MyTable (c1 number, c2 date, c3 number);
Table created.
SQL> insert into MyTable
  2  select 1 as c1, to_date('01/01/2001 12:00:00','DD/MM/YYYY HH24:MI:SS') as c2, to_number(NULL) as c3
  3  from dual union all
  4  select 1 as c1, to_date('01/01/2002 12:00:00','DD/MM/YYYY HH24:MI:SS') as c2, to_number(NULL) as c3
  5  from dual union all
  6  select 1 as c1, to_date('01/01/2003 12:00:00','DD/MM/YYYY HH24:MI:SS') as c2, to_number(NULL) as c3
  7  from dual union all
  8  select 1 as c1, to_date('01/01/2004 12:00:00','DD/MM/YYYY HH24:MI:SS') as c2, to_number(NULL) as c3
  9  from dual union all
10  select 2 as c1, to_date('01/01/2001 12:00:00','DD/MM/YYYY HH24:MI:SS') as c2, to_number(NULL) as c3
11  from dual union all
12  select 2 as c1, to_date('01/01/2002 12:00:00','DD/MM/YYYY HH24:MI:SS') as c2, to_number(NULL) as c3
13  from dual union all
14  select 2 as c1, to_date('01/01/2003 12:00:00','DD/MM/YYYY HH24:MI:SS') as c2, to_number(NULL) as c3
15  from dual union all
16  select 2 as c1, to_date('01/01/2004 12:00:00','DD/MM/YYYY HH24:MI:SS') as c2, to_number(NULL) as c3
17  from dual ;
8 rows created.
SQL>
SQL> select * from MyTable;
        C1 C2               C3
         1 01/01/01
         1 01/01/02
         1 01/01/03
         1 01/01/04
         2 01/01/01
         2 01/01/02
         2 01/01/03
         2 01/01/04
8 rows selected.
SQL>
SQL> merge into MyTable a
  2  using (select c1, c2, row_number() over (partition by c1 order by c2) as c3 from MyTable) b
  3  on (a.c1=b.c1 and a.c2=b.c2)
  4  when matched then update set a.c3=b.c3
  5  when not matched then insert (a.c1,a.c2,a.c3) values (null,null,null);
8 rows merged.
SQL> select * from MyTable order by c1,c2;
        C1 C2               C3
         1 01/01/01          1
         1 01/01/02          2
         1 01/01/03          3
         1 01/01/04          4
         2 01/01/01          1
         2 01/01/02          2
         2 01/01/03          3
         2 01/01/04          4
8 rows selected.
SQL> Nicolas.