On 04/07/07, Igor Tandetnik <[EMAIL PROTECTED]> wrote:
select a1.eid, a1.P, a2.subcase
from barforce_1 a1 join barforce_1 a2 on (a1.P = a2.P)
where not exists
(select * from barforce_1 a3 where a3.eid = a1.eid and a3.P < a1.P)
order by a1.eid;
Excellent. The only trouble is that I don't understand why it works. I
assume that
a3.P < a1.P
is replacing the MIN(P), but I don't following what is happening.
Would you mind explaining?
I'm not sure your query does what you really mean though. Do you
intentionally join on P, rather than eid? Consider:
To cover all cases, I would join on both, but as P is in my case a
double, there are almost never duplicates.
eid P subcase
--------------------
1 10 1
1 20 2
2 30 3
2 40 4
The result of either query (the two should be equivalent) would be
eid P subcase
--------------------
1 10 1
2 30 3
i.e. for each element, the minimum P and the subcase at which it occurred.
Thanks for the help
Jeff
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