with recursive tmp as (
    select 2 as num
    union all
    select num + 1
    from tmp
    where num <= 1000
)
, primes as (
    select num
    from tmp as t1
    where not exists (select 1 
                      from tmp as t2
                      where t2.num < t1.num and t1.num % t2.num = 0)
)
select group_concat(num separator '&') from primes;