SQL Server - assign day and night - sql-server

Question

I have following 2019 data.
Date Calendar_year Weekend_indicator
2019-01-01 2019 weekday
2019-01-01 2019 weekday
2019-01-02 2019 weekday
2019-01-02 2019 weekday
and so on.
I need to give one record a day and another a night value and have it repeated for the entire year's data so that it would look like this.
Date Calendar_year Weekend_indicator day_night
2019-01-01 2019 weekday Day
2019-01-01 2019 weekday Night
2019-01-02 2019 weekday Day
2019-01-02 2019 weekday Night
Here is my code.
DECLARE #Year AS INT,
#FirstDateOfYear DATETIME,
#LastDateOfYear DATETIME
-- You can change #year to any year you desire
SELECT #year = 2019
SELECT #FirstDateOfYear = DATEADD(yyyy, #Year - 1900, 0)
SELECT #LastDateOfYear = DATEADD(yyyy, #Year - 1900 + 1, 0)
-- Creating Query to Prepare Year Data;
WITH cte AS (
SELECT 1 AS DayID,
#FirstDateOfYear AS FromDate,
DATENAME(dw, #FirstDateOfYear) AS Dayname
UNION ALL
SELECT cte.DayID + 1 AS DayID,
DATEADD(d, 1 ,cte.FromDate),
DATENAME(dw, DATEADD(d, 1 ,cte.FromDate)) AS Dayname
FROM cte
WHERE DATEADD(d,1,cte.FromDate) < #LastDateOfYear
)
SELECT c.FromDate AS Date
,#Year as calendar_year
,CHOOSE(datepart(dw, c.FromDate), 'WEEKEND', 'WEEKDAY', 'WEEKDAY',
'WEEKDAY', 'WEEKDAY', 'WEEKDAY', 'WEEKEND') as weekend_indicator
FROM CTE c
CROSS JOIN ( values (1), (2) ) tb (FromDate)
WHERE DayName IN ('Saturday','Sunday')
or dayname not in ('Saturday', 'Sunday')
order by c.FromDate
OPTION (MaxRecursion 1000)
How do I assign the day and the night value and have it repeated?

Answer 1

This simple query might point you in the right direction:
USE TEMPDB
CREATE TABLE #T (DateCol DATE, Calender_Year INT)
INSERT INTO #T VALUES ('20180101', 2018 )
SELECT *
FROM #T
CROSS APPLY (VALUES ('Day'), ('Night') ) AS C (Val)

Answer 2

If you want just to change your code without rewriting it,
add one more row as below:
DECLARE #Year AS INT,
#FirstDateOfYear DATETIME,
#LastDateOfYear DATETIME
-- You can change #year to any year you desire
SELECT #year = 2019
SELECT #FirstDateOfYear = DATEADD(yyyy, #Year - 1900, 0)
SELECT #LastDateOfYear = DATEADD(yyyy, #Year - 1900 + 1, 0);
-- Creating Query to Prepare Year Data;
WITH cte AS (
SELECT 1 AS DayID,
#FirstDateOfYear AS FromDate,
DATENAME(dw, #FirstDateOfYear) AS Dayname
UNION ALL
SELECT cte.DayID + 1 AS DayID,
DATEADD(d, 1 ,cte.FromDate),
DATENAME(dw, DATEADD(d, 1 ,cte.FromDate)) AS Dayname
FROM cte
WHERE DATEADD(d,1,cte.FromDate) < #LastDateOfYear
)
SELECT c.FromDate AS Date
,#Year as calendar_year
,CHOOSE(datepart(dw, c.FromDate), 'WEEKEND', 'WEEKDAY', 'WEEKDAY',
'WEEKDAY', 'WEEKDAY', 'WEEKDAY', 'WEEKEND') as weekend_indicator,
case tb.FromDate when 1 then 'Day' else 'Night' end as day_night -----<<<<<<-----
FROM CTE c
CROSS JOIN ( values (1), (2) ) tb (FromDate)
WHERE DayName IN ('Saturday','Sunday')
or dayname not in ('Saturday', 'Sunday')
order by c.FromDate
OPTION (MaxRecursion 1000)

Answer 3

I use a table variable for create this solution.
DECLARE
#Year int
,#FirstDateOfYear date
,#LastDateOfYear date
,#date_loop date
SET #YEAR = 2019
SELECT
#FirstDateOfYear = DATEADD(yyyy, #Year - 1900, 0)
,#LastDateOfYear = DATEADD(yyyy, #Year - 1900 + 1, 0)
,#date_loop = DATEADD(yyyy, #Year - 1900, 0) --initialize variable for loop
DECLARE #date_table TABLE ([Date] date, [Calendar_year] int, [Weekend_indicator] varchar(10), [day_night] varchar(5))
WHILE #date_loop < #LastDateOfYear
BEGIN
INSERT #date_table
SELECT d.[Date], d.[Calendar_year], d.[Weekend_indicator], ca.[day_night]
FROM (
SELECT
#date_loop AS [Date]
,YEAR(#date_loop) AS [Calendar_year]
,CHOOSE(datepart(dw, #date_loop), 'weekend', 'weekday', 'weekday','weekday', 'weekday', 'weekday', 'weekend') AS [Weekend_indicator]) AS d
CROSS APPLY (
SELECT 'Day' AS [day_night]
UNION
SELECT 'Night'
) AS ca
SET #date_loop = DATEADD(day,1,#date_loop)
END
SELECT *
FROM #date_table

Answer 4

If you don't have a calendar or numbers table, you can use an ad-hoc table
Example
Declare #Date1 date = '2019-01-01'
Declare #Date2 date = '2019-12-31'
Select [Date] = d
,Calendar_year = datepart(YEAR,d)
,Weekend_indicator = case when datename(WEEKDAY,d) in ('Saturday','Sunday') then 'weekend' else 'weekday' end
,day_night
From (
Select Top (DateDiff(DAY,#Date1,#Date2)+1) D=DateAdd(DAY,-1+Row_Number() Over (Order By (Select Null)),#Date1)
From master..spt_values n1,master..spt_values n2
) A
Cross Join (values ('Day'),('Night') ) b(day_night)
Order by D,day_night
Returns
Date Calendar_year Weekend_indicator day_night
2019-01-01 2019 weekday Day
2019-01-01 2019 weekday Night
2019-01-02 2019 weekday Day
2019-01-02 2019 weekday Night
...
2019-12-30 2019 weekday Day
2019-12-30 2019 weekday Night
2019-12-31 2019 weekday Day
2019-12-31 2019 weekday Night

Answer 5

Revised answer: I see an unused (VALUES ...) clause which could be used like so:
CROSS JOIN (VALUES ('Day'), ('Night') ) whatever(day_night)
DB Fiddle