A date string, such as 2007-12-03, compliant with the
full-date format outlined in section 5.6 of the RFC 3339 profile of the ISO 8601 standard for representation of dates and times using the Gregorian calendar.
This scalar is a description of the date, as used for birthdays for example. It cannot represent an instant on the time-line.
When expected as an input type, only RFC 3339 compliant date strings are accepted. All other input values raise a query error indicating an incorrect type.