How to get distinct array elements with postgres?

Question

I have an array with duplicate values in postgres. For example:

SELECT cardinality(string_to_array(\'1,2,3,4,4\', \',\')::int[]) as foo
=> \"foo\"=>\"5         


        

Answer 1

Going off of @klin's accepted answer, I modified it to remove nulls in the process of choosing only the distinct values.

create or replace function public.array_unique_no_nulls(arr anyarray)
returns anyarray
language sql
as $function$
select array_agg(distinct a)
from (
    select unnest(arr) a 
) alias
where a is not null
$function$;