CREATE UNIQUE INDEX IF NOT EXISTS in postgreSQL

Question

Plese I would like to do in PostgreSQL something like

CREATE UNIQUE INDEX IF NOT EXISTS

Any idea?

Answer 1

Another solution that support multiple columns index, based on @Kragh answer

CREATE or replace FUNCTION create_index(_index text, _table text, VARIA

DIC param_args text[]) RETURNS void AS
$$
declare 
   l_count integer;
begin
    select count(*) into l_count
    from pg_indexes
    where schemaname = 'public'
        and tablename = lower(_table)
        and indexname = lower(_index);

    if l_count = 0 then
        EXECUTE format('create index %I on %I (%s)', _index, _table, array_to_string($3,','));
    end if;
END;
$$
LANGUAGE plpgsql;

and then you can use it like any other pg function:

select create_index('events_timestamp_type_idx', 'events', 'timestamp', 'type');