Ron Stevens <sqlite-Y9FGH9USQxS1Z/[EMAIL PROTECTED]> wrote:
On 9/28/06, Igor Tandetnik <[EMAIL PROTECTED]>
wrote:
Ron Stevens
<sqlite-Y9FGH9USQxS1Z/[EMAIL PROTECTED]>
wrote:
The problem is that I can't produce a canonical representation of
the entries in my database. Often times some entries are subsets of
others, but considered equal. It's possible for an entry to be a
subset of two larger entries that aren't equal themselves and still
be equal to each of the larger entries.
Since your relation is not transitive, it is not equivalence. GROUP
BY
does not make sense for it. If you have A ~ B and A ~ C but B !~ C,
how
exactly do you expect these three rows to be grouped?
This case is very uncommon in my data set, but when it does come up I
would want A to show up in two groups, one with A and B and one with
A and C.
I can't think of any way you can trick a SQL statement to include the
same row more than once in the resultset. Relational model just doesn't
work this way.
Can you describe the relation? Exactly what two strings are considered
"equal"?
Igor Tandetnik
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