Обсуждение: Fwd: Re: sum(bool)?

El Viernes 23 Febrero 2001 16:22, escribiste:
> hi there,
>
> i want to add up the "true" values of a comparison like
>
> sum(a>b)
>
> it just doesn't work like this
>
> any workaround?
>
> it is postgresql 7.0 under linux
>
> thanks
>
> olaf

I did exactly the same thing two months ago ....

I created this tiny function:

CREATE FUNCTION bool2int(bool) RETURNS integerAS 'select (case when $1=true then 1 else 0 end)'LANGUAGE 'sql';


You can do:  sum(bool2int(a>b))

easy ??? ;-))


--
Fernando Moyano

Frase del día:
--------------
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Thus spake J.Fernando Moyano
> El Viernes 23 Febrero 2001 16:22, escribiste:
> > i want to add up the "true" values of a comparison like
> >
> > sum(a>b)
> >
> > it just doesn't work like this
> >
> > any workaround?
> 
> I did exactly the same thing two months ago ....
> 
> I created this tiny function:
> 
> CREATE FUNCTION bool2int(bool) RETURNS integer
>     AS 'select (case when $1=true then 1 else 0 end)'
>     LANGUAGE 'sql';
> 
> 
> You can do:  sum(bool2int(a>b))
> 
> easy ??? ;-))

Almost as easy as "SELECT COUNT(*) FROM table WHERE a > b"

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