From: | "Alloni Kramer" <alloni(at)aposiopesis(dot)net> |
---|---|
To: | pgsql-novice(at)postgresql(dot)org |
Subject: | SQL query question |
Date: | 2005-08-08 18:46:42 |
Message-ID: | 4063.64.81.72.73.1123526802.squirrel@mail.aposiopesis.net |
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Lists: | pgsql-novice |
Hi. I've got a problem that I need to figure out, and I can't seem to do
it with the references I have at hand.
Simplified version of problem: We have a table. We'll say it has four
variables, a, b, c, and squelch, all ints. I want to get all values of
these variables for which:
c is within a certain range of values (call it between 3 and 5).
for any given value of a, c is maximum.
- and -
for any given value of a for which c is maximal, b is maximum. That is,
if we have the values of
a b c squelch
1 1 3 5
1 3 3 8
1 1 4 4
1 2 4 6
2 3 5 7
My query should, in this case, get only the last two rows. (The last one
because there is only one row in which a=2, the next to last because c is
maximal for all values where a=1, and b is maximal for all values where c
= the maximal value for a=1.)
Does this make sense? The actual question is more complicated than this,
but if I can figure out this, I can get the actual answer. Please, if you
can, give me an actual sql command that I could use to get the proper
answers from this table.
Thanks a lot for your assistance.
Alloni Kramer
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