From: | Rodger Donaldson <rodgerd(at)diaspora(dot)gen(dot)nz> |
---|---|
To: | pgsql-sql(at)postgresql(dot)org |
Subject: | Applying SUM twice in the same query. |
Date: | 2000-07-15 05:31:25 |
Message-ID: | 20000715173124.A5793@diaspora.gen.nz |
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Thread: | |
Lists: | pgsql-sql |
I have a table structured:
server_name |server_version |number
-------------------+----------------+------
Apache |1.3.11 | 1
Netscape-Enterprise|2.01 | 1
Apache |1.1.3 | 2
Initially I wanted to extract the total count by server_name; this is pretty
straightforward:
select server_name, sum(number)
from web_servers
group by server_name;
...gives the result I expect.
server_name |sum
-------------------+---
Apache | 64
Draupnir | 1
I also want the total number of of servers. This can be obtained with:
select sum(number)
from web_servers;
Again, works fine. What I really want to do with total is to derive a
proportion of number of server:number of servers, something like:
server_name |number|total
-------------------+------+-----
AiNET Apache | 1| 84
Apache | 64| 84
Draupnir | 1| 84
The problem is, I can't forumlate a query to produce it. The closest I got
was:
SELECT ws1.server_name, SUM(ws1.number) AS number, SUM(ws2.number) AS total
FROM web_servers AS ws1, web_servers AS ws2
GROUP BY ws1.server_name;
...which is producing:
server_name |number|total
-------------------+------+-----
AiNET Apache | 19| 84
Apache | 1216| 840
Draupnir | 19| 84
I assume I'm creating a product of the query, but I'm not sure how to fix it.
--
Rodger Donaldson rodgerd(at)diaspora(dot)gen(dot)nz
Driving that fast may also be an autoLART because the acceleration required
to reach a high fraction of c in just a few kilometres may be difficult to
withstand. You will also need a better fuel than gasoline.
-- Steve VanDevender
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