Oracle 18c

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create table t (id, points ) as
select 1, 100 from dual union all
select 2, 130 from dual union all
select 3, 400 from dual union all
select 4, 299 from dual union all
select 5, 50 from dual union all
select 6, 600 from dual union all
select 7, 800 from dual union all
select 22, 700 from dual union all
select 20, 800 from dual union all
select 21, 850 from dual union all
select 23, 970 from dual ;
11 rows affected

select * from t ;


ID
POINTS


1
100

2
130

3
400

4
299

5
50

6
600

7
800

22
700

20
800

21
850

23
970


select id, points
, row_number() over ( order by points ) rn_
from t ;


ID
POINTS
RN_


5
50
1

1
100
2

2
130
3

4
299
4

3
400
5

6
600
6

22
700
7

7
800
8

20
800
9

21
850
10

23
970
11


select 
  t1.id, t1.points as from_
, t2.id, t2.points as to_
from (
  select id, points
  , row_number() over ( order by points ) rn_
  from t
) t1 join (
  select id, points
  , row_number() over ( order by points ) rn_
from t
) t2 on t2.points <= t1.points + 300 and t2.rn_ - t1.rn_ = 3 ;


ID
FROM_
ID
TO_


5
50
4
299

1
100
3
400

6
600
20
800

22
700
21
850

7
800
23
970


select 
  t1.id, t1.points as from_
, t2.id, t2.points as to_
from (
  select id, points
  , row_number() over ( order by points ) rn_
  from t
) t1 join (
  select id, points
  , row_number() over ( order by points ) rn_
from t
) t2 on t2.points <= t1.points + 300  and t2.rn_ - t1.rn_ = 3 
fetch first row only
;


ID
FROM_
ID
TO_


5
50
4
299

ID	POINTS	RN_
5	50	1
1	100	2
2	130	3
4	299	4
3	400	5
6	600	6
22	700	7
7	800	8
20	800	9
21	850	10
23	970	11

ID	POINTS	RN_
5	50	1
1	100	2
2	130	3
4	299	4
3	400	5
6	600	6
22	700	7
7	800	8
20	800	9
21	850	10
23	970	11

ID	POINTS	RN_
5	50	1
1	100	2
2	130	3
4	299	4
3	400	5
6	600	6
22	700	7
7	800	8
20	800	9
21	850	10
23	970	11