DATENAME (datepart, date_exp)
Returns an English character string (a VARCHAR) that represents the datepart of date_exp. For example, a datepart month returns the name of the month such as January, February, and so forth. A datepart weekday returns the day of the week such as Monday, Tuesday, and so forth.
Datepart the part of the date to return, and must be one of the following values.
Date_exp is an expression that returns a DATETIME value, a value that can be implicitly converted to a DATETIME value, or a character string in a DATE format.