Oracle group by statement instance Test

SQL code
Copy codeThe Code is as follows:
Create table test (a VARCHAR2 (20), B VARCHAR2 (20), c NUMBER, d VARCHAR2 (20 ))

Insert into test VALUES ('a1', 'b1', 1, 'T ');
Insert into test VALUES ('a3 ', 'b3', 3, 'T ');
Insert into test VALUES ('a4 ', 'b4', 4, 'T ');
Insert into test VALUES ('a2 ', 'b2', 2, 'T ');
Insert into test VALUES ('XX', 'XX', 5, 'x ');

Insert into test VALUES ('a1', 'b1', 1, 'T ');
Insert into test VALUES ('a3 ', 'b3', 3, 'T ');
Insert into test VALUES ('a4 ', 'b4', 4, 'T ');
Insert into test VALUES ('a2 ', 'b2', 2, 'T ');
Insert into test VALUES ('XX', 'XX', 5, 'x ');
COMMIT;

1. SELECT a, B, SUM (c) FROM test WHERE d = 't'group BY a, B order by a, B;

2. SELECT a, B, SUM (c) FROM test WHERE d = 't'group BY B, a order by a, B;

Summary:For 1, 2, the results should be the same, but the grouping order is different, and the SQL performance should be different.