On 2023-11-13 17:23 +0100, Tom Lane wrote: > Erik Wienhold <e...@ewie.name> writes: > > On 2023-11-13 15:24 +0100, Erik Wienhold wrote: > >> I also noticed that when people say "ISO 8601" they usually mean RFC > >> 3389 or some subset of ISO 8601. > > > Forgot this fine visualization of the differences: > > https://ijmacd.github.io/rfc3339-iso8601/ > > I'm inclined not to change anything here, for a couple of reasons: > > 1. PG accepts a fairly large number of ISO 8601 variants (not all); > not only the RFC 3339 format. So s/ISO 8601/RFC 3339/g would be > incorrect.
I did not say that occurrences of "ISO 8601" should be replaced with "RFC 3339". Just that the docs should have a cautionary note about the SQL standard using a subset of ISO 8601 and that Postgres does not implement (at the moment) all of its date formats. > Besides, I think more people know what ISO 8601 is than > know what RFC 3339 is, so that change would also be confusing. Fair point. > 2. If ijmacd's pretty graphic is correct, then what we say about > 'T' versus space is correct, even if it isn't the whole truth. > I'm not quite sure that ijmacd is correct, though, because of > this bit in 3339: > > NOTE: Per [ABNF] and ISO8601, the "T" and "Z" characters in this > syntax may alternatively be lower case "t" or "z" respectively. > > which suggests that 8601 is also case-insensitive. I don't plan > to go buy a copy of that spec to find out, though. I dug up my old copies (1988/2000/2004) from uni (let me know if you're interested ;) Lower case is allowed if upper case is not available. And it doesn't allow space in any edition. Quote from the 2004 edition: > 3.4.1 Introduction > > NOTE 1 In date and time representations lower case characters may > be used when upper case characters are not available. > > NOTE 2 Encoding of characters for the interchange of dates and times > is not in the scope of this International Standard. > > Unless explicitly allowed by this International Standard the character > "space" shall not be used in the representations. Probably still the same in the current edition but I won't pay for that either. -- Erik
