On 2023-11-11 23:45 +0100, PG Doc comments form wrote: > The following documentation comment has been logged on the website: > > Page: https://www.postgresql.org/docs/16/git.html > Description: > > >ISO 8601 specifies the use of uppercase letter T to separate the date and > time. PostgreSQL accepts that format on input, but on output it uses a space > rather than T, as shown above. This is for readability and for consistency > with RFC 3339 as well as some other database systems.
This note probably refers to section 5.6. of RFC 3339 [1] which allows applications to choose space over "T". > https://www.postgresql.org/docs/current/datatype-datetime.html > > Short answer: T (or t as discouraged alternative). > > After reading on this as much as I could, it turns out the time separator > must be a T or t. What has made think this way is first of all this thread > in the GNU lists where F. Alexander Njemz contacted the authors of RFC3339 > Graham Klyne and Chris Newman asking if T is mandatory and got this response > from Mr. Klyne: > > > In short: "yes" > > > > Per section 5.5, the intent in this draft was to specify a timestamp > format using elements from and compatible with 8601, but eliminating as far > as reasonable any variations that could make timestamp data harder to > process. This includes making the 'T' mandatory in date+time values. > > Just for clarity's sake, this is stated in the section 5.5: > > > Simplicity is achieved by making most fields and punctuation mandatory. But the word "most" certainly leaves some wiggle room. > This clearly clashes with a non-mandatory T and strongly makes me think that > the this syntax in that problematic passage refers to ISO8601 and not > RFC3339. > > https://stackoverflow.com/questions/63783868/what-are-valid-date-time-separators-in-rfc3339-strings/63882162#63882162 [1] https://datatracker.ietf.org/doc/html/rfc3339#section-5.6 -- Erik
