Filling table with weeks of the year skips first week of 2021 - sql-server

Question

So, I am using the following snippet on a procedure, which fills me a temporary table with the first day of each year's week, the week number and month name.
However, when I reach week 53, of 2020, it jumps to week 2 of 2021. This happens because the first of january is in the so called week 53 (which is correct), but it should also be creating another row with the first week of january 2021 (even with the sunday as being in 2020, as it should).
Snippet:
SET DATEFIRST 7
DECLARE #tblSundays TABLE (
[year] INT
,[month] INT
,[week] INT
,[date] DATETIME
)
DECLARE #DateFrom DATETIME = '2020-12-12'
,#DateTo DATETIME = '2021-06-06';
--select #DateFrom,#DateTo;
WITH CTE (dt)
AS (
SELECT #DateFrom
UNION ALL
SELECT DATEADD(d, 1, dt)
FROM CTE
WHERE dt < #DateTo
)
INSERT INTO #tblSundays
SELECT datepart(year, dt)
,datepart(month, dt)
,datepart(week, dt)
,dt
FROM CTE
WHERE datepart("dw", dt) = 1
OPTION (MAXRECURSION 1000)
;
select * from #tblSundays
Is there any way that I can do this within this snippet, or should I create a manual verification?
Thanks!

Answer 1

You should do a couple of little tricks to set week 1 to the first Sunday of the year (tested for the next 30 years):
set datefirst 7
declare #tblSundays table ([year] int, [month] int, [week] int, [date] date)
declare #DateFrom datetime = '20201212', #DateTo datetime = '20510112';
-- Get the next closest Sunday
select #DateFrom = dateAdd(wk, dateDiff(wk, 0, #datefrom - 1 ), 0) + 6
with CTE (dt) as (
select #DateFrom
union all
select dateAdd(dd, 7, dt) from CTE where dt < #DateTo
)
insert into #tblSundays
select datePart(yy, dt),
datePart(mm, dt),
datePart(wk, dt - (1 + (datePart(dy, dt) + 5) % 7) % 7),
dt
from CTE
-- where datepart(dw, dt) = 1
option (maxrecursion 1600);
select *, datePart(wk, [date]) as [standard_wk]
from #tblSundays

Answer 2

I don't see how you could have those two condition on that same snippet, but you could add a second query there to complete what you are trying to do.
Something like this, maybe:
SET datefirst 7
DECLARE #tblSundays TABLE
(
[year] INT,
[month] INT,
[week] INT,
[date] DATETIME
)
DECLARE #DateFrom DATETIME = '2020-12-12',
#DateTo DATETIME = '2021-06-06';
--select #DateFrom,#DateTo;
WITH cte (dt)
AS (SELECT #DateFrom
UNION ALL
SELECT Dateadd(d, 1, dt)
FROM cte
WHERE dt < #DateTo)
INSERT INTO #tblSundays
SELECT Datepart(year, dt),
Datepart(month, dt),
Datepart(week, dt),
dt
FROM cte
WHERE Datepart("dw", dt) = 1
OPTION (maxrecursion 1000);
--second new query
WITH cte (dt)
AS (SELECT #DateFrom
UNION ALL
SELECT Dateadd(d, 1, dt)
FROM cte
WHERE dt < #DateTo)
INSERT INTO #tblSundays
SELECT Datepart(year, dt),
Datepart(month, dt),
Datepart(week, dt),
dt
FROM cte
WHERE Datepart("dw", dt) <> 1
AND Datepart(day, dt) = 1
AND Datepart(week, dt) NOT IN (SELECT week
FROM #tblSundays)
OPTION (maxrecursion 1000);
SELECT *
FROM #tblSundays
ORDER BY year,
month,
week
Would that be OK?