The parameter that specifies which part of the date to return as a new value. For more information, see the "Remarks" section later in this topic.
The value used to increment datepart. This is an expression of the exact numeric or approximate numeric data type categories, or types that can be implicitly converted to float. If you specify a value that is not an integer, the fractional part of the value is discarded. For example, if you specify day for datepart and 1.75 for number, the date is incremented by 1.
An expression that returns a value that can be implicitly converted to datetime, or is a Unicode character string in a date format. For more information about specifying dates, see datetime in Data Types.
If you specify only the last two digits of the year, values less than or equal to the last two digits of the value of the two digit year cutoff configuration option are in the same century as the cutoff year. Values greater than the last two digits of the value of this option are in the century that precedes the cutoff year. For example, if the two digit year cutoff is 2049 (the default), '49' is interpreted as 2049 and '50' is interpreted as 1950. To avoid ambiguity, use four-digit years.