Update table record in a sequence

Question

Hi,
There is a table with name Shift Schedule with the columns as
ID Name Sr_no
1 XXX 55
2 XXX 44
3 XXX 34
4 XXX 23
5 XXX 12
6 YYY 44
7 YYY 22
8 YYY 11
9 YYY 98
10 YYY 78
I need to update the Sr_no from 1 to 5 where ever name xxx and yyyy is there sr_no must be replaced from 1 to 5
There are 4000 records please help me how to do
Thanks
Sudhir

Answer 1

Use MERGE:
merge into shift_schedule a
using ( select id
       ,       sr_no
       ,       row_number() over (partition by name order by id) rn
       from   shift_schedule
      ) b
on (b.id = a.id)
when matched then update set a.sr_no = b.rn;And if you're on 9i, you'll have to add an extra (dummy) line for WHEN NOT MATCHED as well, something like:
SQL> select * from shift_schedule;
        ID NAME      SR_NO
         1 XXX          55
         2 XXX          44
         3 XXX          34
         4 XXX          23
         5 XXX          12
         6 YYY          44
         7 YYY          22
         8 YYY          11
         9 YYY          98
        10 YYY          78
10 rows selected
SQL> merge into shift_schedule a
  2  using ( select id
  3         ,       sr_no
  4         ,       row_number() over (partition by name order by id) rn
  5         from   shift_schedule
  6        ) b
  7  on (b.id = a.id)
  8  when matched then update set sr_no = rn
  9  when not matched then insert (id) values (null);
Done
SQL> select * from shift_schedule;
        ID NAME      SR_NO
         1 XXX           1
         2 XXX           2
         3 XXX           3
         4 XXX           4
         5 XXX           5
         6 YYY           1
         7 YYY           2
         8 YYY           3
         9 YYY           4
        10 YYY           5
10 rows selectedhttp://www.oracle-base.com/articles/9i/SQLNewFeatures9i.php#MERGEStatement
http://www.oracle-base.com/articles/10g/MergeEnhancements10g.php
Edited by: hoek on Oct 25, 2010 2:28 PM changed second example