select * from temp10

k    v
ㅡㅡㅡㅡㅡㅡ
a   {a,b}
a   {c}
b   {d,e}
b   {f}

to

k    v
ㅡㅡㅡㅡㅡㅡ
a   {a,b,c}
b   {d,e,f}

I want these results.
my try ↓

select k,json_agg(v) 
from temp10
group by k 
=
k    v
ㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡ
a   [["a","b"],  ["c"]]
b   [["d","e"],  ["f"]]

select k,array_agg(v) 
from temp10
group by k 
=
SQL Error [2202E]: ERROR: cannot accumulate arrays of different dimensionality

help me
Is there anything lacking in my explanation? Is there anything lacking in my explanation? Is there anything lacking in my explanation?