SQL Server 2017

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CREATE TABLE objectLinks (
   UniqueID int Identity(1,1), 
   ObjectA int,
   ObjectB int
);
INSERT INTO objectLinks (ObjectA, ObjectB)
VALUES (1, 1),
       (1, 2),
       (1, 3),
       (2, 1),
       (2, 3),
       (3, 3),
       (4, 4),
       (4, 5),
       (5, 5);

Select * from objectLinks


UniqueID
ObjectA
ObjectB


1
1
1

2
1
2

3
1
3

4
2
1

5
2
3

6
3
3

7
4
4

8
4
5

9
5
5


DECLARE @Counter INT, 
        @MaxId   INT, 
        @ObjectA INT, 
        @ObjectB  INT,
        @Found   INT

SELECT @Counter = Min(uniqueid), 
       @MaxId = Max(uniqueid) 
FROM   objectLinks 

WHILE( @Counter IS NOT NULL 
       AND @Counter <= @MaxId AND @FOUND is null ) 
  BEGIN 
      DROP TABLE IF EXISTS #tempResult
      SELECT @ObjectA = ObjectA, 
             @ObjectB = ObjectB 
      FROM   objectLinks 
      WHERE  uniqueid = @Counter; 

      WITH cte (uniqueid, ObjectA, ObjectB, chain) 
           AS (SELECT uniqueid, 
                      ObjectA, 
                      ObjectB, 
                      Cast(uniqueid AS VARCHAR(max)) chain 
               FROM   objectLinks 
               WHERE  uniqueid = @Counter 
               UNION ALL 
               SELECT a1.uniqueid, 
                      a1.ObjectA, 
                      a1.ObjectB, 
                      Cast(( chain + ',' + convert(varchar,a1.uniqueid) ) AS VARCHAR(max)) AS 
                      chain 
               FROM   objectLinks a1 
                      INNER JOIN cte p1 
                              ON p1.ObjectB = a1.ObjectB 
                                  OR p1.ObjectA = a1.ObjectA 
               WHERE  chain NOT LIKE '%,' + convert(varchar,a1.uniqueid) + ',%' 
                      AND chain NOT LIKE '%,' + convert(varchar,a1.uniqueid) + '%' 
                      AND chain NOT LIKE '%' + convert(varchar,a1.uniqueid) + ',%' 
                      AND chain <> convert(varchar,a1.uniqueid)) 
      SELECT DISTINCT uniqueid, 
                      ObjectA, 
                      ObjectB
           into #tempResult
       FROM cte
       IF(select count(*) from #tempResult) < 5
       begin
       select * from #tempResult
       SET @Found = 1
      end

      SET @Counter = @Counter + 1 
  END 


uniqueid
ObjectA
ObjectB


7
4
4

8
4
5

9
5
5


 WITH cte (uniqueid, ObjectA, ObjectB, chain) 
           AS (SELECT uniqueid, 
                      ObjectA, 
                      ObjectB, 
                      Cast(uniqueid AS VARCHAR(max)) chain 
               FROM   objectLinks 
               WHERE  uniqueid = 1
               UNION ALL 
               SELECT a1.uniqueid, 
                      a1.ObjectA, 
                      a1.ObjectB, 
                      Cast(( chain + ',' + convert(varchar,a1.uniqueid) ) AS VARCHAR(max)) AS 
                      chain 
               FROM   objectLinks a1 
                      INNER JOIN cte p1 
                              ON p1.ObjectB = a1.ObjectB 
                                  OR p1.ObjectA = a1.ObjectA 
               WHERE  chain NOT LIKE '%,' + convert(varchar,a1.uniqueid) + ',%' 
                      AND chain NOT LIKE '%,' + convert(varchar,a1.uniqueid) + '%' 
                      AND chain NOT LIKE '%' + convert(varchar,a1.uniqueid) + ',%' 
                      AND chain <> convert(varchar,a1.uniqueid)) 
      SELECT DISTINCT uniqueid, 
                      ObjectA, 
                      ObjectB
       FROM cte


uniqueid
ObjectA
ObjectB


1
1
1

2
1
2

3
1
3

4
2
1

5
2
3

6
3
3