Message-ID: <3F855F38.9070803@hotdogrecords.com>
Date: Thu, 09 Oct 2003 09:14:32 -0400
From: Kurt Overberg <kurt@hotdogrecords.com>
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To: pgsql-sql@postgresql.org
Subject: Selecting rows as if they were columns?
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Gang,

I've got what I think should be a pretty simple problem- I just can't 
figure out how I'd do it.  Heck, I can't even figure out how I'd search 
for an answer to this problem.

I've got 2 tables: member and member_attr

Member is just a standard entry for a member.  Very simple:

table member {
id    integer,
name  character varying(30)
}

Member_attr is just a table of name/value pairs, such as:


table memberextra {
memberid     integer,
param1       character varying(512),
param2       character varying(512),
}

where param1 is the name, param2 is the value.

Right now, I can:

select member.id, member.name, member_attr.param1, member_attr.param2 
from member, member_attr where member.id = member_attr.memberid;

...this gives me n rows per member where n = # of attributes for that 
member, like this:

id   |  name   |   param1    |  param2
=======================================
1    |  dave   |  home       |  /home/dave
1    |  dave   |  testing    |  1
2    |  john   |  home       |  /home/john

...is there some way to make this return like this:

id  |  name    |     home   |  testing
======================================
1   |  dave    | /home/dave |  1
2   |  john    | /home/john |

...where it sort of "expands" the rows out into columns?  Am I just 
going about this the wrong way?  Thoughts on the subject would be 
greatly appreciated.

thanks!

/kurt