How to split one record to two?

Question

I am still trying to come up a good example. If you know any, please suggest. I will shoot the question out first.
The base tableA:
colA colB colC colD colE
==================
1 Y 100 23 564
2 N 65 345 23
3 Y 211 940 999
So i need to create a VIEW based on the above table. If the colB has value Y, that record will be split to two. if it's N, just copy all the data
colA colB colC colD colE
==================
1 Y 100
1 N 23 564
2 N 65 345 23
3 Y 211
3 N 940 999
Please keep in mind, this is a simplified view. The real view I created has about 40 columns. 'Union All' seems to be tedious if I have copy like 37 columns with only 3 columns have different values.
Oracle 10gR2.
Thanks.

Answer 1

new2Oracle wrote:
Thanks.
As a learning experience, please explain your approach to this solution.
Edited by: new2Oracle on Mar 22, 2010 1:44 AMYeah, sorry about the first post. I read 2 lines of your sample data and made up the rest in my head so missed a case :)
This should mimic your sample output.
ME_XE?with your_data as
  2  (
  3     select 1 as col1, 'Y' as col2, 100  as col3, 23  as col4, 564  as col5 from dual union all
  4     select 2 as col1, 'N' as col2, 65   as col3, 345 as col4, 23   as col5 from dual union all
  5     select 3 as col1, 'Y' as col2, 211  as col3, 940 as col4, 999  as col5 from dual
  6  ),
  7     dual_data as
  8  (
  9     select 'Y' as col2 from dual union all
10     select 'N' as col2 from dual
11  )
12  select
13     y.col1,
14     case when y.col2 = 'N' then y.col2  else d.col2                                        end as col2,
15     case when y.col2 = 'N' then y.col3  else decode(d.col2, 'Y', y.col3, y.col4)           end as col3,
16     case when y.col2 = 'N' then y.col4  else decode(d.col2, 'Y', to_number(NULL), y.col5)  end as col4,
17     case when y.col2 = 'N' then y.col5  else NULL                                          end as col5
18  from your_data y, dual_data  d
19  where d.col2 = 'Y'
20  or    d.col2 != y.col2
21  order by y.col1, d.col2 desc
22  /
              COL1 COL               COL3               COL4               COL5
                 1 Y                  100
                 1 N                   23                564
                 2 N                   65                345                 23
                 3 Y                  211
                 3 N                  940                999
5 rows selected.
Elapsed: 00:00:03.56
ME_XE?As for the explanation ... you need to make up 2 rows to join to (the data from dual) and then remove rows where you have a N value from your existing data (since you only want a single row in that instance). From there you need to determine what type of data you have in your select statement (hence all the case statements).
Hope that helps.