This document describes a method that can be used to convert a five-digit numeric field in the format of YYDDD into a date data type.
Resolving The Problem
Following is a method that can be used to convert a five-digit numeric field with Julian Date data in the form YYDDD into a field with a date data type:
SELECT DATE('19'||DIGITS(yyddd)) from library/file
To have the results returned in a certain date format, add the CHAR function. If the format of the current job is desired, typically MMDDYY, use the following:
SELECT CHAR(DATE('19'||DIGITS(yyddd))) from library/file
18 December 2019