How to create sequence if not exists

Question

I tried to use code from Check if sequence exists in Postgres (plpgsql).

To create sequence if it does not exists. Running this code two times causes an exception:

Answer 1

I have a function to clean all tables in my database application at any time. It is build dynamically, but the essence is that it deletes all data from each table and resets the sequence. This is the code to reset the sequence of one of the tables:

perform relname from pg_statio_all_sequences where relname = 'privileges_id_seq';
if found then
  select setval ('privileges_id_seq',1, false) into i_result;
end if;

Hope this helps,

Loek

I am using postgres 8.4, I see that you use 9.2. Could make a difference where the information is stored.