SQL Server 2012

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create table test (val int, grp char)
insert into test values 
 (1,'A')
,(2,'A')
,(3,'A')
,(4,'A')
,(1,'B')
,(3,'B')
,(4,'B')
,(2,'C')
,(3,'C')
,(4,'C')
10 rows affected

select t1.val, t2.val, count(*) cnt
from test t1, test t2
where t1.val < t2.val
and t1.grp = t2.grp
group by t1.val, t2.val
having count(*) > 1


val
val
cnt


1
3
2

2
3
2

1
4
2

2
4
2

3
4
3