How to display multiple rows in one records in sql

Syntax :
select
   Col1,
        listagg(COL2, ',') within group (order by COL2) as COL2
From TABLE
Group By
   Col1


Example
Create Table Test_Transpose(Ids Number , Val Number);
Insert Into Test_Transpose Values (1, 11);
Insert Into Test_Transpose Values (1, 12);
Insert Into Test_Transpose Values (1, 13);
Insert Into Test_Transpose Values (1, 14);
Insert Into Test_Transpose Values (1, 15);
Insert Into Test_Transpose Values (2, 21);
Insert Into Test_Transpose Values (2, 22);
Insert Into Test_Transpose Values (2, 23);
Insert Into Test_Transpose Values (2, 24);
Insert Into Test_Transpose Values (2, 25);
Commit;
/

Select * From  Test_Transpose;
Output

IDS	VAL
1	11
1	12
1	13
1	14
1	15
2	21
2	22
2	23
2	24
2	25

Select
   IDS,
        listagg(VAL, ',') within group (order by VAL) as VAL
From Test_Transpose
Group By
   Ids
Output :

IDS	VAL
1	11,12,13,14,15
2	21,22,23,24,25