0 - 2 of 2 tags for listagg

Hello Everyone!
I'm trying to aggregate all the field values of a particular group in one field.
For example, My input table looks like :-


A 1

A 2

B 1

B 2

C 1

C 3

3 null


and my output should look like :-

1 A,B,C


I want to aggregate as "comma-separated values" within a "group by", like MYSQL group_concat: