do I need a table function to do this
I have been given an interesting problem to solve in a postgres db. I was given two tables
t1:
site treatment variable id (pk)
-------------------------------------------------------------
A X BLUE 1A
B Y RED 2B
A Y GREEN 3A
t2:
rowid (pk) timestamp BLUE RED GREEN
-----------------------------------------------------------------------------------------
1 1332493200 3.4 2.1 5.8
2 1332496800 3.2 2.0 5.8
3 1332500400 3.3 2.2 6.0
I need to combine the site and treatment information from t1 with the variable records in t2. I think I will have to combine these one variable at a time. Something like this (I'm not using the word join, because I don't think this is a join in the regular sense. It's more like some kind of crazy pivot table thing!):
t3:
rowid (pk) timestamp BLUE site treatment
-------------------------------------------------------------------------------------
1 1332493200 3.4 A X
2 1332496800 3.2 A X
3 1332500400 3.3 A X
and then:
t4
rowid (pk) timestamp RED site treatment
-------------------------------------------------------------------------------------
1 1332493200 2.1 B Y
2 1332496800 2.0 B Y
3 1332500400 2.2 B Y
Is this even possible?
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Hello Kirk,
Is this even possible?
It looks like if you could "un-pivot" your t2, then you could do a join between that result and t1 and have your desired table. Others may be able to suggest a more direct solution, but I've successfully adapted the one given here, with my own wide-format tables:
https://cgsrv1.arrc.csiro.au/blog/2010/05/14/unpivotuncrosstab-in-postgresql/
Good luck,
Bryan
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<div class="moz-cite-prefix">Do you have a unique key on
site,variable? <br>
If not, what do you want in the treatment column if there are rows
for both treatments X and Y or 2 Xs for a specific site and
variable?<br>
<br>
If your data makes sense, you can pivot table t1 and then full
join t2. <br>
<br>
Sim<br>
<br>
<br>
On 12/29/2012 11:45 PM, Kirk Wythers wrote:<br>
</div>
<blockquote cite="mid:99CCEF6F-37D8-4C1A-B4A7-DA8FF19D5048@umn.edu"
type="cite">
<pre wrap="">I have been given an interesting problem to solve in a postgres db. I was given two tables
t1:
site treatment variable id (pk)
-------------------------------------------------------------
A X BLUE 1A
B Y RED 2B
A Y GREEN 3A
t2:
rowid (pk) timestamp BLUE RED GREEN
-----------------------------------------------------------------------------------------
1 1332493200 3.4 2.1 5.8
2 1332496800 3.2 2.0 5.8
3 1332500400 3.3 2.2 6.0
I need to combine the site and treatment information from t1 with the variable records in t2. I think I will have to combine these one variable at a time. Something like this (I'm not using the word join, because I don't think this is a join in the regular sense. It's more like some kind of crazy pivot table thing!):
t3:
rowid (pk) timestamp BLUE site treatment
-------------------------------------------------------------------------------------
1 1332493200 3.4 A X
2 1332496800 3.2 A X
3 1332500400 3.3 A X
and then:
t4
rowid (pk) timestamp RED site treatment
-------------------------------------------------------------------------------------
1 1332493200 2.1 B Y
2 1332496800 2.0 B Y
3 1332500400 2.2 B Y
Is this even possible?
</pre>
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