The DAY-TO-YYYYDDD function converts argument-1 from the form YYnnn to the form YYYYnnn. Argument-2, when added to the year at the time of execution, defines the ending year of a 100-year interval, or sliding window, into which the year of argument-1 falls.
The type of the function is integer.
(FUNCTION YEAR-TO-YYYY (YY, argument-2) * 1000 + nnn)
where YY = (argument-1/1000) truncated to an integer value
nnn = argument-1 modulus 1000
This function supports a sliding window algorithm. See YEAR-TO-YYYY for a discussion of how to specify a fixed window.