SQL Query Problem

Hi Brahma Prakash Shukla,

You can solve SQL query mentioned problem as like following:

DECLARE @Students TABLE
(
   StudentId		int NOT NULL,
   StudentName		varchar(20),
   AdmissionDate	datetime
)

INSERT INTO @Students (StudentId, StudentName, AdmissionDate) VALUES (1, 'A', '2021-11-20')
INSERT INTO @Students (StudentId, StudentName, AdmissionDate) VALUES (2, 'A', '2022-11-20')
INSERT INTO @Students (StudentId, StudentName, AdmissionDate) VALUES (3, 'B', '2019-11-19')
INSERT INTO @Students (StudentId, StudentName, AdmissionDate) VALUES (4, 'B', '2020-12-19')

declare @days as int = 365

SELECT distinct t1.StudentName,DATEDIFF(day,t1.AdmissionDate,t2.AdmissionDate) - @days as 'Difference', t1.AdmissionDate, t2.AdmissionDate
FROM @Students t1
       INNER JOIN
     @Students t2
       on
         t1.StudentName = t2.StudentName
WHERE DATEDIFF(day,t1.AdmissionDate,t2.AdmissionDate) > @days

Output:

StudentName	Difference	AdmissionDate	AdmissionDate
B	31	2019-11-19 00:00:00.000	2020-12-19 00:00:00.000

For more details:

• DateDiff of 2 dates in the same column SQL
  • https://stackoverflow.com/questions/23366495/datediff-of-2-dates-in-the-same-column-sql

Hope this will help you!