day-of-year-from-dateTime() function extracts the day in the year from a Date and time attribute so it can be used to compare to a value. Values range from 1 (January 1st) to 366 (due to leap years).
This query returns all the logs where the day in the year in
DateAttribute is 30 (for example, “2011-01-30” and “2012-01-30”):
//Logging.Log[day-of-year-from-dateTime(DateAttribute) = 30]