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Re: dynamic crosstab

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On Feb 15, 2008, at 9:56 AM, Balázs Klein wrote:

given that answers for a questionnaire are stored as a
batch

Not in our setup - for all sorts of reasons (preserving responses on a connection failure or restart, monitoring response latency in real time, creating adaptive/branching questionnaires) we send each response separately.

people running reports on will be the ones to notice, i.e. at
retrieval time.

I am not sure - different responses are aggregated into different attributes in different ways - those properties need to be retrieved during scoring/report generation, so being able to create a join directly on a response is a good thing for me. But report generation - in our case it must be a DTP quality PDF - is such a beast anyway that db times dwarf compared to pdf generation.

The problem comes when I need to present the responses themselves in a human-friendly way - as an export or display or report. Do you think there is a way to ensure that the order of the values in the array below is the same for each person?

tbl(eID, aID, value)

Select eID, array_accum(value) from
(
 (Select Distinct eID from tbl) e
  CROSS JOIN
 (Select Distinct aID from tbl) a
) ea
 LEFT OUTER JOIN
tbl USING (eID, aID)
GROUP BY eID

The only way to ever guarantee a particular order is via an ORDER BY clause.

Erik Jones

DBA | Emma®
erik@xxxxxxxxxx
800.595.4401 or 615.292.5888
615.292.0777 (fax)

Emma helps organizations everywhere communicate & market in style.
Visit us online at http://www.myemma.com




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