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9 Replies Latest reply: Jan 5, 2011 5:52 PM by 828920 RSS

Group by preserving the order

jeneesh Guru
Currently Being Moderated
Say for eg: my data is like this
--order by col3
col1 col2  col3
1       5     1
1      10    2
2      2      3
2      5      4
1     15     5
I hav to get o/p as
col1  sum_col2
1       15
2       7
1      15
I have to group by preserving the order
Pls give me suggestions..

jeneesh                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
  • 1. Re: Group by preserving the order
    474126 Newbie
    Currently Being Moderated
    What do you mean preserving the order? In your example, how are you grouping the col2?. If you sum the col2 based on col1, you would get

    col1 sum_col2
    1 30
    2 7

    I don't understand how the col2 is summed up? Can you explain?
  • 2. Re: Group by preserving the order
    jeneesh Guru
    Currently Being Moderated
    Thanks for the reply
    col1 col2  col3
    1       5     1
    1      10    2--summed here, coz col1 changes
    2      2      3
    2      5      4--summed here, coz col1 changes
    1     15     5--summed here, coz col1 changes
    3      25   6--summed here

    Message was edited by:
            jeneesh                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
  • 3. Re: Group by preserving the order
    121256 Newbie
    Currently Being Moderated
    I have to group by preserving the order
    with t as
    ( select 1 as col1,  5 as col2, 1 as col3 from dual union all
      select 1 as col1, 10 as col2, 2 as col3 from dual union all
      select 2 as col1,  2 as col2, 3 as col3 from dual union all
      select 2 as col1,  5 as col2, 4 as col3 from dual union all
      select 1 as col1, 15 as col2, 5 as col3 from dual
    )
    select col1, sum(col2) as col2
      from
      ( select col1, col2, sum(start_of_group) over (order by col3) as group_no
          from
          ( select col1, col2, col3,
                decode(lag(col1) over (order by col3), col1, 0, 1) as start_of_group
              from t
          )
      )
      group by group_no, col1
    ;

             COL1          COL2
    ------------- -------------
                1            15
                2             7
                1            15

    3 rows selected.
  • 4. Re: Group by preserving the order
    jeneesh Guru
    Currently Being Moderated
    Thanks!!!
    Nicely done and saved my life..
  • 5. Re: Group by preserving the order
    474126 Newbie
    Currently Being Moderated
    Elic, Simple and neat solution. I was trying something similar and got this complicated solution.
    SQL> with t
      2  as
      3  (
      4  select 1 col1,5 col2,1 col3 from dual
      5  union all
      6  select 1,10,2 from dual
      7  union all
      8  select 2,2,3 from dual
      9  union all
     10  select 2,5,4 from dual
     11  union all
     12  select 1,15,5 from dual
     13  union all
     14  select 3,25,6 from dual
     15  union all
     16  select 3,10,7 from dual
     17  union all
     18  select 3,5,8 from dual
     19  union all
     20  select 3,15,9 from dual
     21  union all
     22  select 4,5,10 from dual
     23  )
     24  select col1,case when s=1 and rownum = 1 then sm
     25                     when s=1 and rownum <> 1 then  sm-lag(sm,1) over(partition by 1 order by col3)
     26                   when s is null then col2
     27               end     col2
     28  from
     29  (
     30  select col1,col2,col3,s,sm
     31  from
     32  (select col1,col2,col3,
     33         case when col1=lag(col1,1) over(partition by 1 order by col3) and col1<>lead(col1,1) over(partition by 1 order by col3)
     34                  then 1
     35             when col1=lead(col1,1) over(partition by 1 order by col3)
     36                  then 0
     37             else null end s,
     38         sum(col2) over(order by col3) sm
     39  from t
     40  )
     41  where s=1
     42  or s is null
     43  order by col3
     44  )
     45  /
    
          COL1       COL2
    ---------- ----------
             1         15
             2          7
             1         15
             3         55
             4          5
  • 6. Re: Group by preserving the order
    jeneesh Guru
    Currently Being Moderated
    Thanks for ur patience, Mohana..
  • 7. Re: Group by preserving the order
    Aketi Jyuuzou Oracle ACE
    Currently Being Moderated
    Elic's solution is very great.


    another SQL
    SQL> with WorkView as(
      2  select 1 ID,5 Val,1 SortOrder from dual
      3  union all select 1,10,2 from dual
      4  union all select 2,2,3 from dual
      5  union all select 2,5,4 from dual
      6  union all select 1,15,5 from dual
      7  union all select 3,25,6 from dual
      8  union all select 3,10,7 from dual
      9  union all select 3,5,8 from dual
    10  union all select 3,15,9 from dual
    11  union all select 4,5,10 from dual)
    12  select ID,sum(Val) as Val
    13    from (select ID,Val,Last_Value(LagSortOrder ignore nulls) over(order by SortOrder) as LagSortOrder
    14            from (select ID,Val,SortOrder,
    15                         case when ID != Lag(ID) over(order by SortOrder)
    16                              then SortOrder end as LagSortOrder
    17                    from WorkView))
    18  group by ID,LagSortOrder
    19  order by LagSortOrder nulls first;

    ID  VAL
    --  ---
    1   15
    2    7
    1   15
    3   55
    4    5
  • 8. Re: Group by preserving the order
    Aketi Jyuuzou Oracle ACE
    Currently Being Moderated
    I have reserched solution which this problem can solve.
    Therefore, I created this solution.

    Below solution consults "Tabibitozan".
    "Tabibitozan" is Japanese language.
    "Tabibitozan" is one of math problem. (http://www.manabinoba.com/index.cfm/4,757,73,html?year=2002)
    I do not know what "Tabibitozan" is called in English.
    with ValTable as(
    select 1 ID,5 Val,1 SortOrder from dual
    union all select 1,10,2 from dual
    union all select 2,2,3 from dual
    union all select 2,5,4 from dual
    union all select 1,15,5 from dual
    union all select 3,25,6 from dual
    union all select 3,10,7 from dual
    union all select 3,5,8 from dual
    union all select 3,15,9 from dual
    union all select 4,5,10 from dual)
    select ID,sum(Val) as Val
    from (select ID,Val,SortOrder,
           Row_Number() over(order by SortOrder)
          -Row_Number() over(partition by ID order by SortOrder) as makeGroup
          from ValTable)
    group by ID,makeGroup
    order by min(SortOrder);
    ID  VAL
    --  ---
    1   15
    2    7
    1   15
    3   55
    4    5
    In above solution,
    I imagined that there are 5 people called X,A,B,C, and D.

    X always walks 1m. (Row_Number() over(order by SortOrder))

    When ID = 1, A walks 1m. (Row_Number() over(partition by ID order by SortOrder))
    When ID = 2, B walks 1m. (Row_Number() over(partition by ID order by SortOrder))
    When ID = 3, C walks 1m. (Row_Number() over(partition by ID order by SortOrder))
    When ID = 4, D walks 1m. (Row_Number() over(partition by ID order by SortOrder))

    Then,
    I derived distance between X and A.
    I derived distance between X and B.
    I derived distance between X and C.
    I derived distance between X and D.

    Then, I made group using these distance. (group by ID,makeGroup)



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  • 9. Re: Group by preserving the order
    828920 Newbie
    Currently Being Moderated
    Elic wrote:

    <DIV class=jive-quote>I have to group by preserving the order</DIV><PRE>with t as

    ( select 1 as col1, 5 as col2, 1 as col3 from dual union all

    select 1 as col1, 10 as col2, 2 as col3 from dual union all

    select 2 as col1, 2 as col2, 3 as col3 from dual union all

    select 2 as col1, 5 as col2, 4 as col3 from dual union all

    select 1 as col1, 15 as col2, 5 as col3 from dual

    )

    select col1, sum(col2) as col2

    from

    ( select col1, col2, sum(start_of_group) over (order by col3) as group_no

    from

    ( select col1, col2, col3,

    <font face="tahoma,verdana,sans-serif" size="1" color="#000">decode</font>(lag(col1) over (order by col3), col1, 0, 1) as start_of_group

    from t

    )

    )

    group by group_no, col1

    ;



    COL1 COL2

    <HR>-------------

    1 15

    2 7

    1 15



    3 rows selected.

    </PRE>
    I've learned a lot, Your answer is very helpful.