This function is only available if the Analysis AddIn is installed.
Syntax:
DAYSINMONTH(date)
returns the number of days in the month in which date lies.
Example:
DAYSINMONTH("2012-02-14")
returns 29, the number of days in February 2012 (2012 is a leap year).
Issues:
DAYSINMONTH is not part of the forthcoming ODFF international standard, and should not be regarded as portable. An alternative would be DAY(DATE(YEAR(date);MONTH(date)+1;0)).