Get day of week in SQL Server 2005/2008

402
votes

If I have a date 01/01/2009, I want to find out what day it was e.g. Monday, Tuesday, etc...

Is there a built-in function for this in SQL Server 2005/2008? Or do I need to use an auxiliary table?

10
sqlsql-serverdatetime
If you have a table containing lookups for date portions, you have generally done something wrong. SQL Server's date functions are many and robust so any data you need to extract from a date can be readily done on a datetime column. – Benjamin Autin
auxiliary tables are very useful for date calculations, it is not unusual to have a calendar auxiliary table... – aaaa
"Useful for date calculations" is highly dubious. Most date calculations can be handled without any kind of auxiliary table and will perform better, too. In some cases, a plain Numbers table will do the job--no need for a table with actual dates in it. The only reason I have seen that an actual calendar table needed is when the rules for which days are work days and which days are not are very complicated. What I HAVE seen far too often is people using date tables because they don't know how to do it any other way. Then they have to populate the date table every so often. Silly. – ErikE
I'll eat my words if you can show me a use for calendar tables that 1) isn't for complex holiday/workday rules, 2) can't be easily done with built-in functions, and 3) only if not #2, then a Numbers table works just as well and doesn't require populating the table with specific dates. – ErikE
Data warehouses make extensive use of calendar tables. The precalculated months, quarters, years, etc provide the end users with fields they can filter/aggregate against. – David Rushton

10 Answers

743
votes

Use DATENAME or DATEPART:

SELECT DATENAME(dw,GETDATE()) -- Friday
SELECT DATEPART(dw,GETDATE()) -- 6
98
votes

Even though SQLMenace's answer has been accepted, there is one important SET option you should be aware of

SET DATEFIRST

DATENAME will return correct date name but not the same DATEPART value if the first day of week has been changed as illustrated below.

declare @DefaultDateFirst int
set @DefaultDateFirst = @@datefirst
--; 7 First day of week is "Sunday" by default
select  [@DefaultDateFirst] = @DefaultDateFirst 
    
set datefirst @DefaultDateFirst
select datename(dw,getdate()) -- Saturday
select datepart(dw,getdate()) -- 7

--; Set the first day of week to * TUESDAY * 
--; (some people start their week on Tuesdays...)
set datefirst 2
select datename(dw,getdate()) -- Saturday
--; Returns 5 because Saturday is the 5th day since Tuesday.
--; Tue 1, Wed 2, Th 3, Fri 4, Sat 5
select datepart(dw,getdate()) -- 5 <-- It's not 7!
set datefirst @DefaultDateFirst
31
votes
SELECT  CASE DATEPART(WEEKDAY,GETDATE())  
    WHEN 1 THEN 'SUNDAY' 
    WHEN 2 THEN 'MONDAY' 
    WHEN 3 THEN 'TUESDAY' 
    WHEN 4 THEN 'WEDNESDAY' 
    WHEN 5 THEN 'THURSDAY' 
    WHEN 6 THEN 'FRIDAY' 
    WHEN 7 THEN 'SATURDAY' 
END
14
votes

EUROPE:

declare @d datetime;
set @d=getdate();
set @dow=((datepart(dw,@d) + @@DATEFIRST-2) % 7+1);
12
votes

To get a deterministic value for the day of week for a given date you could use a combination of DATEPART() and @@datefirst. Otherwise your dependent on the settings on the server.

Check out the following site for a better solution: MS SQL: Day of Week

The day of week will then be in the range 0 to 6, where 0 is Sunday, 1 is Monday, etc. Then you can use a simple case statement to return the correct weekday name.

9
votes

With SQL Server 2012 and onward you can use the FORMAT function

SELECT FORMAT(GETDATE(), 'dddd')
3
votes

this is a working copy of my code check it, how to retrive day name from date in sql

CREATE Procedure [dbo].[proc_GetProjectDeploymentTimeSheetData] 
@FromDate date,
@ToDate date

As 
Begin
select p.ProjectName + ' ( ' + st.Time +' '+'-'+' '+et.Time +' )' as ProjectDeatils,
datename(dw,pts.StartDate) as 'Day'
from 
ProjectTimeSheet pts 
join Projects p on pts.ProjectID=p.ID 
join Timing st on pts.StartTimingId=st.Id
join Timing et on pts.EndTimingId=et.Id
where pts.StartDate >= @FromDate
and pts.StartDate <= @ToDate
END
1
votes

If you don't want to depend on @@DATEFIRST or use DATEPART(weekday, DateColumn), just calculate the day of the week yourself.

For Monday based weeks (Europe) simplest is:

SELECT DATEDIFF(day, '17530101', DateColumn) % 7 + 1 AS MondayBasedDay

For Sunday based weeks (America) use:

SELECT DATEDIFF(day, '17530107', DateColumn) % 7 + 1 AS SundayBasedDay

This return the weekday number (1 to 7) ever since January 1st respectively 7th, 1753.

1
votes

You can use DATEPART(dw, GETDATE()) but be aware that the result will rely on SQL server setting @@DATEFIRST value which is the first day of week setting (In Europe default value 7 which is Sunday).

If you want to change the first day of week to another value, you could use SET DATEFIRST but this may affect everywhere in your query session which you do not want.

Alternative way is to explicitly specify the first day of week value as parameter and avoid depending on @@DATEFIRST setting. You can use the following formula to achieve that when need it:

(DATEPART(dw, GETDATE()) + @@DATEFIRST + 6 - @WeekStartDay) % 7 + 1

where @WeekStartDay is the first day of the week you want for your system (from 1 to 7 which means from Monday to Sunday).

I have wrapped it into below function so we can reuse it easily:

CREATE FUNCTION [dbo].[GetDayInWeek](@InputDateTime DATETIME, @WeekStartDay INT)
RETURNS INT
AS
BEGIN
    --Note: @WeekStartDay is number from [1 - 7] which is from Monday to Sunday
    RETURN (DATEPART(dw, @InputDateTime) + @@DATEFIRST + 6 - @WeekStartDay) % 7 + 1 
END

Example usage: GetDayInWeek('2019-02-04 00:00:00', 1)

It is equivalent to following (but independent to SQL server DATEFIRST setting): 

SET DATEFIRST 1
DATEPART(dw, '2019-02-04 00:00:00')
-1
votes

You may find this version usefull.

-- Test DATA
select @@datefirst
create table #test (datum datetime)
insert #test values ('2013-01-01')
insert #test values ('2013-01-02')
insert #test values ('2013-01-03')
insert #test values ('2013-01-04')
insert #test values ('2013-01-05')
insert #test values ('2013-01-06')
insert #test values ('2013-01-07')
insert #test values ('2013-01-08')
-- Test DATA

select  Substring('Sun,Mon,Tue,Wed,Thu,Fri,Sat,Sun,Mon,Tue,Wed,Thu,Fri,Sat',
        (DATEPART(WEEKDAY,datum)+@@datefirst-1)*4+1,3),Datum
        from #test