SQL Server 2019

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CREATE TABLE dates (
From_Date date,	
To_Date	date);
INSERT INTO dates VALUES
('2022-03-01','2022-03-13'),	
('2022-03-14','2022-03-31');	
2 rows affected

SELECT
  From_Date ,
  DATENAME(ww, From_Date) FromWeek,
  To_Date,
  DATENAME(ww, To_Date) ToWeek,
  1 + CAST( DATENAME(ww, To_Date) AS INT)
    - CAST( DATENAME(ww, From_Date) AS INT) WeekDiff
FROM dates;


From_Date
FromWeek
To_Date
ToWeek
WeekDiff


2022-03-01
10
2022-03-13
12
3

2022-03-14
12
2022-03-31
14
3


SELECT
  From_Date ,
  DATENAME(ww, From_Date) FromWeek,
  To_Date,
  DATENAME(ww, To_Date) ToWeek,
  1 + CAST( DATENAME(ww, DATEADD(day, -1, To_Date)) AS INT)
    - CAST( DATENAME(ww, DATEADD(day, -1, From_Date)) AS INT) WeekDiff
FROM dates;


From_Date
FromWeek
To_Date
ToWeek
WeekDiff


2022-03-01
10
2022-03-13
12
2

2022-03-14
12
2022-03-31
14
3