How to get date between 2 days name from a table - sql

Question

I have 2 day names as input (For Example: "Friday" and "Monday". I need to get need to get all dates from a table in between those Friday and Monday (Friday, Saturday, Sunday, Monday) . If it is "Tuesday" and "Thursday" i need to get (Tuesday, Wednesday and Thursday )
My table is
If days are friday and monday. My Output should be
I tried this
SELECT
EMPLID, DUR, DayName, TRC
FROM DayTable
WHERE
DayName BETWEEN 'FRIDAY' AND 'MONDAY'
ORDER BY DUR ASC
but not working, Help me to solve this. Thanks in Advance

Answer 1

Try this query:
DECLARE #From int,#To int
Create Table #Days(Id int, DayOfWeek Varchar(100))
Insert into #Days Values
(1,'Sunday'),
(2,'Monday'),
(3,'Tuesday'),
(4,'Wednesday'),
(5,'Thursday'),
(6,'Friday'),
(7,'Saturday')
Select #From = Id from #Days where DayOfWeek = 'Friday'
Select #To = Id from #Days where DayOfWeek = 'Monday'
Select T.EMPLID, T.DUR, T.DayName, T.TRC from DayTable T
Inner Join #Days D on T.DayName = D.DayOfWeek AND (D.Id <= #To Or D.Id >= #From)
Hope this helps!
Update
Here's the same solution in a table valued function:
create function dbo.DaysBetween (
#DayFrom nvarchar(16)
, #DayTo nvarchar(16)
) returns #results table ([DayName] nvarchar(16))
as
begin
declare #daynames table (id smallint not null, [dayname] nvarchar(16) not null)
insert #daynames(id, [dayname])
values (0, 'Monday'),(1, 'Tuesday'),(2, 'Wednesday'),(3, 'Thursday'),(4, 'Friday'),(5, 'Saturday'),(6, 'Sunday')
declare #dayFromInt smallint
, #dayToInt smallint
select #dayFromInt = id from #daynames where [dayname] = #DayFrom
if (#dayFromInt is null)
begin
--hacky trick from https://stackoverflow.com/a/4681815/361842
set #dayFromInt = cast(('Invalid Day From Name: ' + #DayFrom) as int)
return
end
select #dayToInt = id from #daynames where [dayname] = #DayTo
if (#dayToInt is null)
begin
--hacky trick from https://stackoverflow.com/a/4681815/361842
set #dayToInt = cast(('Invalid Day To Name: '+ #DayTo) as int)
return
end
insert #results ([dayname])
select [dayname]
from #daynames
where
(
(#dayFromInt <= #dayToInt) and (id between #dayFromInt and #dayToInt)
or
(#dayFromInt > #dayToInt) and (id >= #dayFromInt or id <= #dayToInt)
)
return
end
go
Here are some example scenarios:
select * from dbo.DaysBetween('Monday','Friday')
select * from dbo.DaysBetween('Friday','Monday')
select * from dbo.DaysBetween('Tuesday','Thursday')
select * from dbo.DaysBetween('Thursday','Tuesday')
select * from dbo.DaysBetween('Christmasday','Monday')
go --required to get this result after the above error
select * from dbo.DaysBetween('Monday','Holiday')
To use this in your query, you'd do:
SELECT EMPLID
, DUR
, DayName
, TRC
FROM DayTable
WHERE
[DayName] in
(
select [DayName]
from dbo.DaysBetween('Friday','Monday')
)
ORDER BY DUR ASC

Answer 2

You cannot use the between operator like that. Datename returns a string, and the between operator is tru for all daynames that lexigraphically falls between "Friday" and "Monday".
I would suggest using
DayName in ('FRIDAY','SATURDAY','SUNDAY', 'MONDAY' )
Or use
set datefirst 2
...
where datepart(weekday,DUR)>3

Answer 3

If you use the DATEPART function on DUR, you will get the integer representation for the weekday.
So updating your WHERE clause:
SELECT
EMPLID, DUR, DayName, TRC
FROM DayTable
WHERE
DATEPART(weekday, DUR) BETWEEN 2 AND 6
ORDER BY DUR ASC
Where datepart will give you the weekday integer: SUN -> 1, MON-> 2 ... SAT -> 7
https://learn.microsoft.com/pt-br/sql/t-sql/functions/datepart-transact-sql

Answer 4

If you know your sql server's setting start day of the week is Sunday, then you can try this query :
SELECT
EMPLID, DUR, DayName, TRC
FROM DayTable
WHERE
DATEPART(WEEKDAY, DUR) <= 2 or DATEPART(WEEKDAY, DUR) >= 6
ORDER BY DUR ASC
Where week index of Monday = 2 and Friday = 6