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),
    ('BankAccountId', 1),
    ('BankAccountId', 8),
    ('ItemTypeId', 1),
    ('VATId', 1),
    ('InOut', 5),
    ('FundTypeId', 5),
    ('CurrencyId', 5),
    ('VATPer', 1),
    ('ItemId', 8)
;
12 rows affected

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


LineGroupBy
IdList


BankAccountId
1,5,8

CurrencyId
5

FundTypeId
5

InOut
5

ItemId
1,8

ItemTypeId
1,8

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 (select distinct LineGroupBy, Id from temp) t2
  WHERE Groups.LineGroupBy = t2.LineGroupBy
  ORDER BY t2.id
  FOR XML PATH('')
), 1, 1, '') AS IdList
FROM (SELECT DISTINCT LineGroupBy FROM temp) AS Groups


LineGroupBy
IdList


BankAccountId
1,5,6,8

CurrencyId
5,6

FundTypeId
5,6

InOut
5,6

ItemId
1,6,8

ItemTypeId
1,6,8

VATId
1,6

VATPer
1,6


with CTE as (
    SELECT Groups.LineGroupBy, STUFF(
        (
          SELECT ',' + CAST(t2.id AS VARCHAR(20))
          FROM (SELECT DISTINCT LineGroupBy, Id FROM temp) t2
          WHERE Groups.LineGroupBy = t2.LineGroupBy
          ORDER BY t2.id
          FOR XML PATH('')
        ), 1, 1, '') AS IdList
    FROM (SELECT DISTINCT LineGroupBy FROM temp) AS Groups
  )
SELECT LineGroupBy, IdList
FROM CTE
WHERE IdList = (
    SELECT STUFF((
        SELECT ',' + CAST(id AS VARCHAR(20))
        FROM (SELECT DISTINCT Id FROM temp) t
        ORDER BY id
    FOR XML PATH('')
    ), 1, 1, '') 
  )


LineGroupBy
IdList


BankAccountId
1,5,6,8

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

LineGroupBy	IdList
BankAccountId	1,5,6,8
CurrencyId	5,6
FundTypeId	5,6
InOut	5,6
ItemId	1,6,8
ItemTypeId	1,6,8
VATId	1,6
VATPer	1,6