Postgres 13

By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.

CREATE TABLE public.table_1 (
    id serial NOT NULL,
    date_start date NOT NULL,
    date_end date NULL
);

CREATE TABLE public.table_2 (
    id serial NOT NULL,
    date_start date NOT NULL,
    date_end date NULL
);
alter table public.table_1 add constraint my_constraint_2 EXCLUDE USING gist (daterange(date_start, coalesce(date_end, 'infinity'),  '[]') WITH &&);
alter table public.table_2 add constraint my_constraint_2 EXCLUDE USING gist (daterange(date_start, coalesce(date_end, 'infinity'),  '[]') WITH &&);
ERROR:  relation "my_constraint_2" already exists


SELECT *
FROM pg_indexes
WHERE indexname = 'my_constraint_2'


schemaname
tablename
indexname
tablespace
indexdef


public
table_1
my_constraint_2
null
CREATE INDEX my_constraint_2 ON public.table_1 USING gist (daterange(date_start, COALESCE(date_end, 'infinity'::date), '[]'::text))