select
    max(decode(mod(a.a_num,7),1,decode(a.b_num,null,''||a.a_num,'['||a.a_n
um||']'))) as col1,
    max(decode(mod(a.a_num,7),2,decode(a.b_num,null,''||a.a_num,'['||a.a_n
um||']'))) as col2,
    max(decode(mod(a.a_num,7),3,decode(a.b_num,null,''||a.a_num,'['||a.a_n
um||']'))) as col3,
    max(decode(mod(a.a_num,7),4,decode(a.b_num,null,''||a.a_num,'['||a.a_n
um||']'))) as col4,
    max(decode(mod(a.a_num,7),5,decode(a.b_num,null,''||a.a_num,'['||a.a_n
um||']'))) as col5,
    max(decode(mod(a.a_num,7),6,decode(a.b_num,null,''||a.a_num,'['||a.a_n
um||']'))) as col6,
    max(decode(mod(a.a_num,7),0,decode(a.b_num,null,''||a.a_num,'['||a.a_n
um||']'))) as col7
from (
    select
        ceil((a.rnum)/7) as id,
        a.rnum as a_num,
        b.rnum as b_num
    from
        (select rownum as rnum from dual connect by level<=45) a
        left outer join
        (
            select
                *
            from (
                    select
                        rownum as rnum,
                        dbms_random.value(1,1000000000000) as rval
                    from dual
                    connect by level<=45
                    order by rval desc
                )
            where rownum<=6
            order by rnum) b
    on a.rnum=b.rnum
    order by a.rnum
)a
group by a.id