I'm not sure if the bug-fix for "natural self-join" solves this, but here we go.
This query yields a cartesian product:
SELECT COUNT(X) FROM A NATURAL JOIN (B NATURAL JOIN C NATURAL JOIN D);
However, if I rearrange the tables I get the desired result:
SELECT COUNT(X) FROM (B NATURAL JOIN C NATURAL JOIN D) NATURAL JOIN A;
The relationship between A and D is a "1 to N" relationship, where as B, C and
D all have a "1 to 1" relationship.
Hence, A has fewer entries than D for each row. B+C+D limits the search space
radically, so I would expect both the queries above to be fast.
Why is the first one extremely slow? Is it a bug?
Thanks.
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