union query doubt:

From: javier garcia <andresjavier(dot)garcia(at)wanadoo(dot)es>
To: "pgsql-sql(at)postgresql(dot)org" <pgsql-sql(at)postgresql(dot)org>
Subject: union query doubt:
Date: 2002-12-11 16:21:43
Message-ID: 200212111616.gBBGG3Q29502@natura.cebas.csic.es
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Hi;
I've got a table with three fields: DATE, POINT, FLOW. The POINT field can
have values among 1 and 6. So, for a same date I have six different points
with the correspondings flows.
I would like to make a query to obtain something like:
DATE POINT1 POINT2 POINT3 POINT4 POINT5 POINT6

where for a date I have the flows data of the different points.

I think that I would need to establish different alias for the same field. Is
this possible?

Perhaps something like:

SELECT date, flow AS POINT1 FROM samples WHERE POINT=1
UNION ALL
SELECT date, flow AS POINT2 FROM samples WHERE POINT=2
UNION ALL
SELECT date, flow AS POINT3 FROM samples WHERE POINT=3
...;

and a SELECT over the result of this subselect, that groups by date, or so?

Thanks for you help.

Javier

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