select *

from (values (1, 2), (2, 7), (5, 7), (7, 10), (10, 11), (12, 13), (13, 14)) v(x, y)

),

tt as (

select v.x, v.y

from t cross apply

(values (x, y), (y, x)) v(x, y)

),

cte as (

select (case when tt.x < tt.y then tt.x else tt.y end) as lowest, v.val, tt.x, tt.y, convert(varchar(max), concat(',', tt.x, ',', tt.y, ',')) as vals

from tt cross apply

(values (x), (y)) v(val)

union all

select (case when tt.y < cte.lowest then tt.y else cte.lowest end) as lowest, cte.val, cte.x, tt.y, concat(cte.vals, tt.y, ',') as vals

from cte join

tt

on cte.y = tt.x and cte.vals not like concat('%,', tt.y, ',%')

union all

select (case when tt.x < cte.lowest then tt.x else cte.lowest end) as lowest, cte.val, tt.x, cte.y, concat(cte.vals, tt.x, ',') as vals

from cte join

tt

on cte.x = tt.y and cte.vals not like concat('%,', tt.x, ',%')

)

select min(lowest), val

from cte

group by val