Hi,
Perhaps a CTE would help?SELECT
delta - avg(delta))/stddev(delta) AS deltaNorm
, (echo - avg(echo))/stddev(echo) AS echoNorm
, (foxtrot - avg(foxtrot))/stddev(foxtrot) AS foxtrotNorm
FROM t_subs
)
SELECT
deltaNorm + echoNorm + foxtrotNorm AS normSum
FROM NormCTE
ORDER BY normSum DESC
HTH
2014-08-03 13:20 GMT+02:00 Tim Smith <gb10hkzo-postgres@xxxxxxxxxxx>:
Hi,
I'm on Postgres 9.3.5, however I think my knowledge of Postgres is not deep enough to help me with this challenge, so here I am reaching out to the community !
Let's say I have a table as follows :
create table t_subs (alpha text,bravo text,charlie numeric,delta numeric,echo numeric,foxtrot numeric);
And let's say I have a view that does some basic filtering on that table
create view v_subs as select alpha,delta,echo,foxtrot from t_subs where charlie>=5 and bravo not in ('this','that');
What I need to do is order the output of the view based on normalised output of delta,echo and foxtrot.
So, what I need to do is :
1/ Calculate normalised values for each column and row....
deltaNorm = (delta - avg(delta))/stddev(delta)
echoNorm = (echo - avg(echo))/stddev(echo)
foxtrotNorm = (foxtrot - avg(foxtrot))/stddev(foxtrot)
normSum = deltaNorm + echoNorm + foxtrotNorm
2/ order desc on normSum
The problem is I cannot seem to find a way to do this in one query.
Thanks in advance for your help !
Tim
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