Обсуждение: Math Query Help

i'm trying to work out some match queries to find
yields.

this is what i want to do...

yield = pass / total:

(select count(inspect_pass) from t_inspect where
inspect_pass = true)/(select count(inspect_pass) from
t_inspect)

i get the following error:

ERROR:  syntax error at or near "/" at character 70

how can i fix this?

tia...

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----- Original Message -----
From: <operationsengineer1@yahoo.com>
To: <pgsql-novice@postgresql.org>
Sent: Tuesday, May 09, 2006 3:59 PM
Subject: [NOVICE] Math Query Help


> (select count(inspect_pass) from t_inspect where
> inspect_pass = true)/(select count(inspect_pass) from
> t_inspect)
>
> i get the following error:
>
> ERROR:  syntax error at or near "/" at character 70
>
> how can i fix this?

This should work:

SELECT((select count(inspect_pass) from t_inspect where
inspect_pass = true)/(select count(inspect_pass) from
 t_inspect))

Regards,
George

> ----- Original Message -----
> From: <operationsengineer1@yahoo.com>
> To: <pgsql-novice@postgresql.org>
> Sent: Tuesday, May 09, 2006 3:59 PM
> Subject: [NOVICE] Math Query Help
>
>
> > (select count(inspect_pass) from t_inspect where
> > inspect_pass = true)/(select count(inspect_pass)
> from
> > t_inspect)
> >
> > i get the following error:
> >
> > ERROR:  syntax error at or near "/" at character
> 70
> >
> > how can i fix this?
>
> This should work:
>
> SELECT((select count(inspect_pass) from t_inspect
> where
> inspect_pass = true)/(select count(inspect_pass)
> from
>  t_inspect))
>
> Regards,
> George

George, this format does run, but for other newbs out
there, it will yield a result of 0 unless you cast the
results as numeric like so:

SELECT(
  (select count(inspect_pass)
  from t_inspect
  where inspect_pass = true)::numeric
  /
  (select count(inspect_pass)
  from t_inspect)::numeric
)::numeric(10,2)

in my case, this returns 0.64

thanks for sharing this syntax.  my searches were all
coming up empty.

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