DATENAME (Transact-SQL)

datepart

Is the part of the date to return. The following table lists all valid datepart arguments. User-defined variable equivalents are not valid.

datepart	Abbreviations
year	yy, yyyy
quarter	qq, q
month	mm, m
dayofyear	dy, y
day	dd, d
week	wk, ww
weekday	dw, w
hour	hh
minute	mi, n
second	ss, s
millisecond	ms
microsecond	mcs
nanosecond	ns
TZoffset	tz
ISO_WEEK	ISOWK, ISOWW

date

Is an expression that can be resolved to a time, date, smalldatetime, datetime, datetime2, or datetimeoffset value. date can be an expression, column expression, user-defined variable, or string literal.

To avoid ambiguity, use four-digit years. For information about two-digit years, see Configure the two digit year cutoff Server Configuration Option.

nvarchar

• Each datepart and its abbreviations return the same value.

The return value depends on the language environment set by using SET LANGUAGE and by the Configure the default language Server Configuration Option of the login. The return value is dependant on SET DATEFORMAT if date is a string literal of some formats. SET DATEFORMAT does not affect the return value when the date is a column expression of a date or time data type.

When the date parameter has a date data type argument, the return value depends on the setting specified by using SET DATEFIRST.

SELECT DATENAME(year, '12:10:30.123')
    ,DATENAME(month, '12:10:30.123')
    ,DATENAME(day, '12:10:30.123')
    ,DATENAME(dayofyear, '12:10:30.123')
    ,DATENAME(weekday, '12:10:30.123');

SELECT DATENAME(hour, '2007-06-01')
    ,DATENAME(minute, '2007-06-01')
    ,DATENAME(second, '2007-06-01');

DATENAME can be used in the select list, WHERE, HAVING, GROUP BY, and ORDER BY clauses.

In SQL Server 2012, DATENAME implicitly casts string literals as a datetime2 type. This means that DATENAME does not support the format YDM when the date is passed as a string. You must explicitly cast the string to a datetime or smalldatetime type to use the YDM format.

The following example returns the date parts for the specified date.

SELECT DATENAME(datepart,'2007-10-30 12:15:32.1234567 +05:10');

Here is the result set.

Reference