YEAR/MONTH/DAY(t) 
YEAR(t), MONTH(t) and DAY(t) are functions (extraction) that extract the year, month and day from the specified date or time stamp value.
Value t: When used in a function, the expression t must supply a date, a time stamp, or an alphanumeric value that matches the current date or time stamp format.
t |
Result of the Function |
|---|---|
YEAR(t), MONTH(t) or DAY(t) |
Numeric value (year, month, day) |
t is a NULL value |
NULL value |