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

You need some procedural code for this, something like this (untested!):

do
$$
declare 
   l_count integer;
begin
  select count(*)
     into l_count
  from pg_indexes
  where schemaname = 'public'
    and tablename = 'your_table'
    and indexname = 'your_index_name';

  if l_count = 0 then 
     execute 'create unique index public.your_index_name on public.your_table(id)';
  end if;

end;
$$