On Wed, 2020-11-18 at 22:49 +0900, Fujii Masao wrote: > On 2020/11/12 17:14, Laurenz Albe wrote: > > > On Wed, 2020-11-11 at 18:19 +0100, Laurenz Albe wrote: > > > > Table 9.54 in page > > > > https://www.postgresql.org/docs/current/functions-range.html states > > > > that the > > > > functions lower and upper return NULL if the requested bound is > > > > infinite. If > > > > the element type of the range contains the special values infinity and > > > > -infinity, this is not correct, as those values are returned if > > > > explicitly > > > > used as either bound. > > > +1 > > > Perhaps it would be better to say > > > NULL if the range is empty or has no lower/upper bound > > I agree this description looks a bit confusing. But according to the section > "Infinite (Unbounded) Ranges" (*1), we already call "lower/upper bound > omitted" just infinite. So I don't think the current description is incorrect. > > (*1) > https://www.postgresql.org/docs/devel/rangetypes.html#RANGETYPES-INFINITE
That is correct, but I'd argue that it would be better to clarify the paragraph too, in particular: The functions lower_inf and upper_inf test for infinite lower and upper bounds of a range, respectively. should better read The functions lower_inf and upper_inf test for omitted lower and upper bounds of a range, respectively. The rest of the paragraph is pretty unambiguous. Independent of this, I think that my patch for "upper" and "lower" would make the documentation clearer. Yours, Laurenz Albe
