DATENAME (Transact-SQL)

Článek
12/30/2022

Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance Azure Synapse Analytics Analytics Platform System (PDW)

This function returns a character string representing the specified datepart of the specified date.

See Date and Time Data Types and Functions (Transact-SQL) for an overview of all Transact-SQL date and time data types and functions.

Transact-SQL syntax conventions

Syntax

DATENAME ( datepart , date )

Arguments

datepart
The specific part of the date argument that DATENAME will return. This table lists all valid datepart arguments.

Note

DATENAME does not accept user-defined variable equivalents for the datepart arguments.

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

An expression that can resolve to one of the following data types:

date
datetime
datetimeoffset
datetime2
smalldatetime
time

For date, DATENAME will accept a column expression, expression, string literal, or user-defined variable. Use four-digit years to avoid ambiguity issues. See Configure the two digit year cutoff Server Configuration Option for information about two-digit years.

Return Type

nvarchar

Return Value

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 depends on SET DATEFORMAT if date is a string literal of some formats. SET DATEFORMAT does not change 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 SET DATEFIRST.

TZoffset datepart Argument

If the datepart argument is TZoffset (tz) and the date argument has no time zone offset, DATEADD returns 0.

smalldatetime date Argument

When date is smalldatetime, DATENAME returns seconds as 00.

Default Returned for a datepart That Is Not in the date Argument

If the data type of the date argument does not have the specified datepart, DATENAME will return the default for that datepart only if the date argument has a literal .

For example, the default year-month-day for any date data type is 1900-01-01. This statement has date part arguments for datepart, a time argument for date, and DATENAME returns 1900, January, 1, 1, Monday.

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');

If date is specified as a variable or table column, and the data type for that variable or column does not have the specified datepart, DATENAME will return error 9810. In this example, variable @t has a time data type. The example fails because the date part year is invalid for the time data type:

DECLARE @t time = '12:10:30.123';   
SELECT DATENAME(year, @t);

Remarks

Use DATENAME in the following clauses:

GROUP BY
HAVING
ORDER BY
SELECT <list>
WHERE

In SQL Server, DATENAME implicitly casts string literals as a datetime2 type. In other words, 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.

Examples

This example returns the date parts for the specified date. Substitute a datepart value from the table for the datepart argument in the SELECT statement:

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

Here's the result set.

datepart	Return value
year, yyyy, yy	2007
quarter, qq, q	4
month, mm, m	October
dayofyear, dy, y	303
day, dd, d	30
week, wk, ww	44
weekday, dw	Tuesday
hour, hh	12
minute, n	15
second, ss, s	32
millisecond, ms	123
microsecond, mcs	123456
nanosecond, ns	123456700
TZoffset, tz	+05:10
ISO_WEEK, ISOWK, ISOWW	44

Azure Synapse Analytics and Analytics Platform System (PDW)