select K, listagg(case when chgv1 = 1 then v1 else null end,',') within group (order by v1) as v1lst, --Only consider cases in listagg when rows have changed
listagg(case when chgv2 = 1 then v2 else null end,',') within group (order by v2) as v2lst --Only consider cases in listagg when rows have changed
from (
select k, v1, v2,
row_number() over (partition by k,v1 order by v1 ) as chgv1, --Detect changes in v1. In this case it's 1.
row_number() over (partition by k,v2 order by v1 ) as chgv2 --Detect changes in v1. In this case it's 1.
from t)
group by k;
