[SQL] Print Prime Numbers

출처:

https://www.hackerrank.com/challenges/print-prime-numbers/problem?isFullScreen=true

문제:

Write a query to print all prime numbers less than or equal to . Print your result on a single line, and use the ampersand (&) character as your separator (instead of a space).
For example, the output for all prime numbers $\le$10 would be:

2&3&5&7

답:

with numbers as (
    select level num
    from dual
    where level > 1
    connect by level <= 1000
)
select listagg(n.num, '&') within group(order by n.num)
    from numbers n
where not exists (select num
                    from numbers e
                 where e.num < n.num
                    and mod(n.num, e.num) = 0
                 );

참고:

https://yurimyurim.tistory.com/16