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Selecting records with equal vectors

Posted by Dr. Wolfgang Hintze on 03/19/07 13:41

Suppose we have a table tab ín which there are fields X, Y, ...
which designate the coordinates of n-dimensional vectors.

We would like to select all records which contain the same vectors

Exapmple n=2

ID X Y
01 1 2
02 1 3
03 1 2
04 2 3

The select statement should yield the records with ID 01 and 03
(vectors (1,2))

There might of course be several sets of equal vector records.

In the end we would like to have a list of all those equal vector
records.

In my practical case n=2 is sufficient but a general formulation would
be interesting as well.

Any help and suggestions would be greatly appreciated.

Wolfgang

 

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