1 create or replace function generate_unique_changeme()
2 returns text language sql
4 select 'http://changeme_' || string_agg (substr('abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz0123456789', ceil (random() * 62)::integer, 1), '')
5 from generate_series(1, 20)