Postgresql:Generate Sequence

Question

The query below generates a line of DNA sequence

prepare dna_length(int) as
with t1 as (select chr(65) as s union select chr(67) union select chr(71) union select         


        

Answer 1

Something like this?

select x, string_agg((array['A', 'C', 'G', 'T'])[1 + floor(random() * 4)], '')
from generate_series(1, 20, 1) gsn(n) cross join
     generate_series(1, 10, 1) gsx(x)
group by x