Professional SQL Server™ 2005 Programming

A.4. Date and Time Functions

The date and time functions perform operations on values that have datetime and smalldatetime data types or that are character data types in a date form. They are:

• DATEADD

• DATEDIFF

• DATENAME

• DATEPART

• DAY

• GETDATE

• GETUTCDATE

• MONTH

• YEAR

SQL Server recognizes eleven "dateparts" and their abbreviations, as shown in the following table:

Datepart	Abbreviations
year	yy, yyyy
quarter	qq, q
month	mm, m
dayofyear	dy, y
day	dd, d
week	wk, ww
weekday	dw
hour	hh
minute	mi, n
second	ss, s
millisecond	ms

A.4.1. DATEADD

The DATEADD function adds an interval to a date and returns a new date. The syntax is as follows:

DATEADD(<datepart>, <number>, <date>)

The datepart argument specifies the time scale of the interval (day, week, month, etc.) and may be any of the dateparts recognized by SQL Server. The number argument is the number of dateparts that should be added to the date.

A.4.2. DATEDIFF

The DATEDIFF function returns the difference between two specified dates in a specified unit of time (for example: hours, days, weeks). The syntax is as follows:

DATEDIFF(<datepart>, <startdate>, <enddate>)

The datepart argument may be any of the dateparts recognized by SQL Server and specifies the unit of time to be used.

A.4.3. DATENAME

The DATENAME function returns a string representing the name of the specified datepart (for example: 1999, Thursday, July) of the specified date. The syntax is as follows:

DATENAME(<datepart>, <date>)

A.4.4. DATEPART

The DATEPART function returns an integer that represents ...