Oracle 18c

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create table qz_products (
   id    integer primary key
 , name  varchar2(20) not null unique
);

create table qz_wishlist (
   user_name   varchar2(10) not null
 , id_or_name  varchar2(20) not null
);

begin
insert into qz_products values (1042, 'Bowling ball' );
insert into qz_products values (1088, 'Bottle opener');
insert into qz_products values (2021, 'Bikini top'   );
insert into qz_products values (2069, 'Beach parasol');

insert into qz_wishlist values ('Bob'  ,'1042');
insert into qz_wishlist values ('Bob'  ,'Bottle opener');
insert into qz_wishlist values ('Betty','Bikini top');
insert into qz_wishlist values ('Betty','2069');
end;
/
1 rows affected

select w.user_name, p.id, p.name
from qz_wishlist w inner join qz_products p
on 
    to_number(w.id_or_name default null on conversion error) = p.id
    or w.id_or_name = p.name


USER_NAME
ID
NAME


Bob
1042
Bowling ball

Bob
1088
Bottle opener

Betty
2021
Bikini top

Betty
2069
Beach parasol

USER_NAME	ID	NAME
Bob	1042	Bowling ball
Bob	1088	Bottle opener
Betty	2021	Bikini top
Betty	2069	Beach parasol