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?
Regards,
--
Hitoshi Harada