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Message Posted: Tue, 06 Mar 2007 @ 16:59:38 GMT


     
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Subj:   Re: Performance of a self join
 
From:   Dieter Noeth

Goutham P wrote:

  Can you please explain what you meant by saying joining these tables together? In the derived table B, I am having the aggregation on only fewer dimensional columns (dim 1 - dim 5) . Where as in the OLAP function used for table A, I am aggregating on different set of dimensional columns (dim 1 - dim 4). I have to join these two tables as they both give different perspective of data.  


Just do the OLAP calculation in the Derived Table, OLAP functions can work on aggregates:

     select
     A.*, value3
     from A,
      (
        select
        dim1 ,
        dim2 ,
        dim3 ,
        dim4 ,
        dim5 ,
        metric1 / count(metric2) as value2 ,
        Value2 / sum(Value2) over
                    (partition by dim1, dim2, dim3, dim4) as value3
        from A
        group by 1,2,3,4,5
      ) B
     where A.dim1 = B.dim1
     and A.dim2 = B.dim2
     and A.dim3 = B.dim3
     and A.dim4 = B.dim4
     and A.dim5 = B.dim5
     and A.dim6 = B.dim6

Dieter



     
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