How to speed up table creation in ORACLE?

Question

Oracle

Good afternoon!
I'm trying to create a table, the code is as follows:

create table TAB_TMP 
as
with date as
(select 
    trunc(sysdate) - level as d
    from dual
        where to_char(trunc(sysdate)-level,'d')='7'
            or level = 1
            or (trunc(sysdate)-level)=last_day(trunc(sysdate)-level)
       connect by trunc(sysdate)-level >=
            (select min(end_date) from TABLE1)
)
select d "DATE",
    c.code "CODE",
    a.id "ID",
    a.amt "BALANCE"
from TABLE1 a
join dates b
    on b.d between a.start_date and a.end_date
join TABLE2 c
    on c.idx=a.idx

The problem is that the table is very large, the code takes too long, is there any way to optimize and speed up the process?