Turn postgres date representation into ISO 8601 string

Question

I\'m trying to format a Postgres date representation into a ISO 8601 string. I\'m assuming that there is a Postgres function that can do it, but I found the documentation sh

Answer 1

This is a terse way to "turn a PostgreSQL date representation into an ISO 8601 string":

SELECT to_json(now())#>>'{}'

It uses the #>> operator in combination with the to_json() function, which can both be found on this page: https://www.postgresql.org/docs/current/functions-json.html

The operator "Get[s] JSON object at specified path as text". However when you specify an empty array literal '{}' as the path, it specifies the root object.

Compare this method to similar methods:

SELECT
to_char(now(), 'YYYY-MM-DD"T"HH24:MI:SSOF') AS most_lengthy, -- See note: *
trim(both '"' from to_json(now())::text) AS a_bit_lengthy,
to_json(now())::text AS unwanted_quotes,
to_json(now())#>>'{}' AS just_right

It's shorter but produces the same results.

* Also, JavaScript will not parse the first method's output via the Date() constructor, because it expects a simplification of the ISO 8601 which only accepts time zones in (+/-)HH:mm or Z format, but OF returns (+/-)HH format without the minutes, UNLESS the input timezone is a fraction of an hour, e.g. using SET timezone=-4.5; at the beginning of the session. Alternatively you could manually append your timezone as a string to the lengthy version and exclude the OF