SQL Server 2022

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CREATE TABLE temp (
    LineGroupBy varchar(20),
    Id INTEGER
);
INSERT INTO temp (LineGroupBy, Id)
VALUES
    ('ItemTypeId', 8),
    ('ItemId', 1),
    ('BankAccountId', 5),
    ('ItemTypeId', 1),
    ('VATId', 1),
    ('InOut', 5),
    ('FundTypeId', 5),
    ('CurrencyId', 5),
    ('VATPer', 1),
    ('ItemId', 8)
;
10 rows affected

SELECT Groups.LineGroupBy, STUFF((
    SELECT ',' + CAST(t2.id AS VARCHAR(20))
    FROM temp t2
    WHERE Groups.LineGroupBy = t2.LineGroupBy
    FOR XML PATH('')
), 1, 1, '') AS IdList
FROM (SELECT DISTINCT LineGroupBy FROM temp) AS Groups


LineGroupBy
IdList


BankAccountId
5

CurrencyId
5

FundTypeId
5

InOut
5

ItemId
1,8

ItemTypeId
8,1

VATId
1

VATPer
1


INSERT INTO temp (LineGroupBy, Id)
VALUES
    ('ItemTypeId',6),
    ('ItemId',6),
    ('BankAccountId',6),
    ('ItemTypeId',6),
    ('VATId',6),
    ('InOut',6),
    ('FundTypeId',6),
    ('CurrencyId',6),
    ('VATPer',6)
  ;
9 rows affected

SELECT Groups.LineGroupBy, STUFF((
    SELECT ',' + CAST(t2.id AS VARCHAR(20))
    FROM temp t2
    WHERE Groups.LineGroupBy = t2.LineGroupBy
    FOR XML PATH('')
), 1, 1, '') AS IdList
FROM (SELECT DISTINCT LineGroupBy FROM temp) AS Groups


LineGroupBy
IdList


BankAccountId
5,6

CurrencyId
5,6

FundTypeId
5,6

InOut
5,6

ItemId
1,8,6

ItemTypeId
8,1,6,6

VATId
1,6

VATPer
1,6


SELECT * FROM temp T WHERE T.Id=1
INTERSECT
SELECT * FROM temp T WHERE T.Id=5
INTERSECT
SELECT * FROM temp T WHERE T.Id=8


LineGroupBy
Id

LineGroupBy	IdList
BankAccountId	5
CurrencyId	5
FundTypeId	5
InOut	5
ItemId	1,8
ItemTypeId	8,1
VATId	1
VATPer	1