SQL Server 2014

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-- Data table that I have
CREATE TABLE DataTable (
        Date Date,
        CapVersion varchar(100),
        CaseNumber int
    );
INSERT INTO DataTable (Date, CapVersion, CaseNumber)
VALUES 
('2020-12-02', 'CAP A', 1002),
('2020-12-02', 'CAP A', 1003),
('2020-12-02', 'CAP A', 1004),
--compare CAP A with CAP B
('2020-12-11', 'CAP B', 1002),
('2020-12-11', 'CAP B', 1003),
--compare CAP B with CAP C
('2020-12-14', 'CAP C', 1003),
('2020-12-14', 'CAP C', 1004),
('2020-12-14', 'CAP C', 1005),
--compare CAP C with CAP D
('2020-12-15', 'CAP D', 1005),
('2020-12-15', 'CAP D', 1007);

SELECT * FROM DataTable;

;WITH DataTableBase AS 
(
	SELECT Date, CapVersion, ROW_NUMBER() OVER (ORDER BY Date) AS seq
	FROM DataTable
	GROUP BY Date, CapVersion
), DataTableSections AS 
( 
	SELECT Date, CapVersion, CaseNumber, DENSE_RANK() OVER (ORDER BY Date) AS seq	
	FROM DataTable 	
), DataTableCombined AS
(
	SELECT dt1.seq, dt2.seq AS seqBefore, dt1.CaseNumber, dt2.CaseNumber AS CaseNumberBefore, dt1.Date, dt1.CapVersion, dt2.Date AS DateBefore, dt2.CapVersion AS CapVersionBefore
	FROM DataTableSections AS dt1
	FULL OUTER JOIN DataTableSections AS dt2 ON dt1.seq = dt2.seq + 1 AND dt1.CaseNumber = dt2.CaseNumber
)

SELECT dt.seq
	, dt.Date
	, dt.CapVersion	
	, COUNT(CASE WHEN dt.seq != 1 AND CaseNumberBefore IS NULL THEN 1 END) AS CaseNumberAdded
	, COUNT(CASE WHEN CaseNumber IS NULL THEN 1 END) AS CaseNumberRemoved
	, COUNT(CASE WHEN (dt.seq = 1) OR (CaseNumber IS NOT NULL AND CaseNumberBefore IS NOT NULL) THEN 1 END) AS CaseNumberExisiting
FROM DataTableBase AS dt
INNER JOIN DataTableCombined AS dtc ON dt.seq = COALESCE(dtc.seq, dtc.seqBefore + 1)
GROUP BY dt.seq, dt.Date, dt.CapVersion

Date	CapVersion	CaseNumber
2020-12-02	CAP A	1002
2020-12-02	CAP A	1003
2020-12-02	CAP A	1004
2020-12-11	CAP B	1002
2020-12-11	CAP B	1003
2020-12-14	CAP C	1003
2020-12-14	CAP C	1004
2020-12-14	CAP C	1005
2020-12-15	CAP D	1005
2020-12-15	CAP D	1007

seq	Date	CapVersion	CaseNumberAdded	CaseNumberRemoved	CaseNumberExisiting
1	2020-12-02	CAP A	0	0	3
2	2020-12-11	CAP B	0	1	2
3	2020-12-14	CAP C	2	1	1
4	2020-12-15	CAP D	1	2	1

Warning: Null value is eliminated by an aggregate or other SET operation.