tim.rfc_3339_sec is modelled after the --rfc-3339=sec option of the date shell command. It returns an alphabetically sortable representation of a date without separating date and time with T or appending any fractional seconds or time zone information. select tim.rfc_3339_sec(sysdate) rfc_3339, tim.iso_8601 (sysdate) iso_8601 from dual; -- -- RFC_3339 ISO_8601 -- -------------------- -------------------- -- 2021-07-03 11:19:00 2021-07-03T11:19:00Z