Обсуждение: a simple transform
I've thrashed at this transform for quite a while and come up empty. The crosstab() functions, and the documented examples, all do something more complex than I need. I can do this after the fact trivially in python with the 'zip()' function, but I need it real-time from a view or function. Of course I could be overlooking the obvious (it's happened before!) I have this:attr1 attr2 attr3------ ------ ------ cat1 0.34 0.12 0.22 cat2 0.11 0.67 0.31 and need it transposed thus: cat1 cat2 ----- ----- attr1 0.34 0.11 attr2 0.12 0.67 attr3 0.22 0.31 in case it adds motivation (;^/), cat1 and cat2 are democrat & republican; the attr's are campaign issues; the values are "aboutness" derived from a text similarity measure tia Karl
Karl Grossner wrote: > I've thrashed at this transform for quite a while and come up empty. The > crosstab() functions, and the documented examples, all do something more > complex than I need. I can do this after the fact trivially in python with > the 'zip()' function, but I need it real-time from a view or function. > > Of course I could be overlooking the obvious (it's happened before!) > > I have this: > attr1 attr2 attr3 > ------ ------ ------ > cat1 0.34 0.12 0.22 > cat2 0.11 0.67 0.31 > > and need it transposed thus: > cat1 cat2 > ----- ----- > attr1 0.34 0.11 > attr2 0.12 0.67 > attr3 0.22 0.31 I see no response; so I thought I'd take a stab at it. I don't have 8.3 yet so I cannot test my idea. I read the docs, and I think what you need to do is create SQL that will produce cat attr val ---- ----- ---- cat1 attr1 0.34 cat1 attr2 0.12 cat1 attr3 0.22 cat2 attr1 0.11 cat2 attr2 0.67 cat2 attr3 0.31 That pass the SQL into crosstab().
On Tue, Sep 16, 2008 at 6:37 AM, Frank Bax <fbax@sympatico.ca> wrote: > > That pass the SQL into crosstab(). It might be interesting to look at this blog also: http://okbob.blogspot.com/#7449458148004287481 -- Regards, Richard Broersma Jr. Visit the Los Angeles PostgreSQL Users Group (LAPUG) http://pugs.postgresql.org/lapug