MySQL 8.0

By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.

select version();


version()


8.0.30


create table my_table (col_a int, col_b int, col_c int);
insert into my_table values (1,1,1),(1,1,2),(1,2,1),(1,2,2),(2,1,1),(2,1,2),(2,2,1),(2,2,2);
    select sum(col_a) as col_a, sum(col_b) as col_b, sum(col_c) as col_c, count(*),
        case (col_a is not null) + (col_b is not null) + (col_c is not null) when 3 then 'col_a,col_b,col_c' when 2 then 'col_a,col_b' when 1 then 'col_a' end grouped_by
    from my_table
    group by col_a, col_b, col_c with rollup
    having grouped_by is not null
    order by grouped_by, col_a, col_b, col_c


col_a
col_b
col_c
count(*)
grouped_by


4
6
6
4
col_a

8
6
6
4
col_a

2
2
3
2
col_a,col_b

2
4
3
2
col_a,col_b

4
2
3
2
col_a,col_b

4
4
3
2
col_a,col_b

1
1
1
1
col_a,col_b,col_c

1
1
2
1
col_a,col_b,col_c

1
2
1
1
col_a,col_b,col_c

1
2
2
1
col_a,col_b,col_c

2
1
1
1
col_a,col_b,col_c

2
1
2
1
col_a,col_b,col_c

2
2
1
1
col_a,col_b,col_c

2
2
2
1
col_a,col_b,col_c


    select sum(col_a) as col_a, sum(col_b) as col_b, sum(col_c) as col_c, count(*)    from my_table
    group by col_a, col_b, col_c
    order by col_a, col_b, col_c


col_a
col_b
col_c
count(*)


1
1
1
1

1
1
2
1

1
2
1
1

1
2
2
1

2
1
1
1

2
1
2
1

2
2
1
1

2
2
2
1


    select sum(col_a) as col_a, sum(col_b) as col_b, sum(col_c) as col_c, count(*)    from my_table
    group by col_a, col_b
    order by col_a, col_b


col_a
col_b
col_c
count(*)


2
2
3
2

2
4
3
2

4
2
3
2

4
4
3
2


    select sum(col_a) as col_a, sum(col_b) as col_b, sum(col_c) as col_c, count(*)    from my_table
    group by col_a
    order by col_a


col_a
col_b
col_c
count(*)


4
6
6
4

8
6
6
4

col_a	col_b	col_c	count(*)	grouped_by
4	6	6	4	col_a
8	6	6	4	col_a
2	2	3	2	col_a,col_b
2	4	3	2	col_a,col_b
4	2	3	2	col_a,col_b
4	4	3	2	col_a,col_b
1	1	1	1	col_a,col_b,col_c
1	1	2	1	col_a,col_b,col_c
1	2	1	1	col_a,col_b,col_c
1	2	2	1	col_a,col_b,col_c
2	1	1	1	col_a,col_b,col_c
2	1	2	1	col_a,col_b,col_c
2	2	1	1	col_a,col_b,col_c
2	2	2	1	col_a,col_b,col_c