SQL DATEPART(dw,date) need monday = 1 and sunday = 7 - sql

Question

I have a Query where I get the WeekDay of a date but by default:
Sunday = 1
Moday = 2
etc.
The function is:
DATEPART(dw,ads.date) as weekday
I need the result so:
Sunday = 7
Monday = 1
etc.
Is there any shortcut to do this? Or I will have to do a CASE statement?

Answer 1

This will do it.
SET DATEFIRST 1;
-- YOUR QUERY
Examples
-- Sunday is first day of week
set datefirst 7;
select DATEPART(dw,getdate()) as weekday
-- Monday is first day of week
set datefirst 1;
select DATEPART(dw,getdate()) as weekday

Answer 2

You can use a formula like:
(weekday + 5) % 7 + 1
If you decide to use this, it would be worth running through some examples to convince yourself that it actually does what you want.
addition:
for not to be affected by the DATEFIRST variable (it could be set to any value between 1 and 7) the real formula is :
(weekday + ##DATEFIRST + 5) % 7 + 1

Answer 3

You can tell SQL Server to use Monday as the start of the week using DATEFIRST like this:
SET DATEFIRST 1

Answer 4

I would suggest that you just write the case statement yourself using datename():
select (case datename(dw, aws.date)
when 'Monday' then 1
when 'Tuesday' then 2
when 'Wednesday' then 3
when 'Thursday' then 4
when 'Friday' then 5
when 'Saturday' then 6
when 'Sunday' then 7
end)
At least, this won't change if someone changes the parameter on the day of the week when weeks begin. On the other hand, it is susceptible to the language chosen for SQL Server.

Answer 5

You can use this formula regardless of DATEFIRST setting :
((DatePart(WEEKDAY, getdate()) + ##DATEFIRST + 6 - [first day that you need] ) % 7) + 1;
for monday = 1
((DatePart(WEEKDAY, getdate()) + ##DATEFIRST + 6 - 1 ) % 7) + 1;
and for sunday = 1
((DatePart(WEEKDAY, getdate()) + ##DATEFIRST + 6 - 7 ) % 7) + 1;
and for friday = 1
((DatePart(WEEKDAY, getdate()) + ##DATEFIRST + 6 - 5 ) % 7) + 1;

Answer 6

Another solution is the following:
ISNULL(NULLIF(DATEPART(dw,DateField)-1,0),7)

Answer 7

This is caused by the account the SQL Server service is run under. For example;
If the SQL Server Service is run under DOMAIN\MyUserAccount then this will need to be a login and set with the relevant Language.
If this account isn't set then SQL Server will default to the sa account and the Language that runs under.
I found that our sa account was set to English which had Monday as DW = 2. The DOMAIN\MyUserAccount Account was setup and changed to British English and DW for Monday was being returned as 1.
Hope this helps

Answer 8

Simply subtract one day from your ads.date field and use in DATEPART function:
DATEPART(dw,DATEADD(day,-1,ads.date)) as weekday

Answer 9

I think this could work:
select
case when datepart(dw,[Date]) = 1 then 7 else DATEPART(DW,[Date])-1 end as WeekDay

Answer 10

Try this:
CREATE FUNCTION dbo.FnDAYSADDNOWK(
#addDate AS DATE,
#numDays AS INT
) RETURNS DATETIME AS
BEGIN
WHILE #numDays > 0 BEGIN
SET #addDate = DATEADD(day, 1, #addDate)
IF DATENAME(DW, #addDate) <> 'sunday' BEGIN
SET #numDays = #numDays - 1
END
END
RETURN CAST(#addDate AS DATETIME)
END

Answer 11

Looks like the DATEFIRST settings is the only way, but it's not possible to make a SET statement in a scalar/table valued function. Therefore, it becomes very error-prone to the colleagues following your code. (become a trap to the others)
In fact, SQL server datepart function should be improved to accept this as parameter instead.
At the meantime, it looks like using the English Name of the week is the safest choice.

Answer 12

-- Monday is first day of week set datefirst 1; select DATEPART(dw,getdate()) as weekday
SQLChao answer still works prefectly well

Answer 13

You would need to set DATEFIRST. Take a look at this article. I believe this should help.
https://learn.microsoft.com/en-us/sql/t-sql/statements/set-datefirst-transact-sql

Answer 14

I think
DATEPART(dw,ads.date - 1) as weekday
would work.