YEAR
Returns the year as a number according to the internal calculation rules.
YEAR(数字)
「serial_number」处给出的是要转换成相对应年份数的日期内部序列数。
YEAR() returns the integer part of the year.
「=YEAR(1)」返回 1899
「=YEAR(2)」返回 1900
「=YEAR(33333.33)」返回 1991
=YEAR(DATEVALUE("2010-09-28")) returns 2010.
