Re: Reason why set-value functions not allowed in GREATEST(), etc?

2010/2/22 Hitoshi Harada <umi.tanuki@gmail.com>:
> I just wonder why generate_series() is not allowed in GREATEST syntax.
> Looking through execQual.c,  almost all syntactic evaluations like
> COALESCE, ARRAY[], ROW() doesn't allow set-value functions. Could
> someone tell the underlying reason?
>
> Also, using variadic functions introduced since 8.4, I hope we can
> remove the special syntax cases for them by replacing them with normal
> variadic functions. Is it sane idea?

we cannot do it :(

we cannot ensure similar coercion for these functions with variadic
functions. Variadic functions use a generic coercion.

Regards
Pavel Stehule

>
> Regards,
>
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> Hitoshi Harada
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