Left Outer Join via a link table, using min() to restrict join to one row - oracle

Question

I am trying to write an Oracle SQL query to join two tables that are linked via a link table (by that I mean a table with 2 columns, each a foreign key to the primary tables). A min() function is to be used to limit the results from the left outer join to a single row.
My model consists of "parents" and "nephews". Parents can have 0 or more nephews. Parents can be enabled or disabled. Each nephew has a birthday date. The goal of my query is:
Print a single row for each enabled parent, listing that parent's oldest nephew (ie the one with the min(birthday)).
My problem is illustrated here at sqlfiddle: http://sqlfiddle.com/#!4/9a3be0d/1
I can form a query that lists all of the nephews for the enabled parents, but that is not good enough- I just want one row per parent which includes just the oldest nephew. Forming the where clause to the outer table seems to be my stumbling block.
My tables and sample data:
create table parent (parent_id number primary key, parent_name varchar2(50), enabled int);
create table nephew (nephew_id number primary key, birthday date, nephew_name varchar2(50));
create table parent_nephew_link (parent_id number not null, nephew_id number not null);
parent table:
+----+-------------+---------+
| id | parent_name | enabled |
+----+-------------+---------+
| 1 | Donald | 1 |
+----+-------------+---------+
| 2 | Minnie | 0 |
+----+-------------+---------+
| 3 | Mickey | 1 |
+----+-------------+---------+
nephew table:
+-----------+------------+-------------+
| nephew_id | birthday | nephew_name |
+-----------+------------+-------------+
| 100 | 01/01/2017 | Huey |
+-----------+------------+-------------+
| 101 | 01/01/2016 | Dewey |
+-----------+------------+-------------+
| 102 | 01/01/2015 | Louie |
+-----------+------------+-------------+
| 103 | 01/01/2014 | Morty |
+-----------+------------+-------------+
| 104 | 01/01/2013 | Ferdie |
+-----------+------------+-------------+
parent_nephew_link table:
+-----------+-----------+
| parent_id | nephew_id |
+-----------+-----------+
| 1 | 100 |
+-----------+-----------+
| 1 | 101 |
+-----------+-----------+
| 1 | 102 |
+-----------+-----------+
| 3 | 103 |
+-----------+-----------+
| 3 | 104 |
+-----------+-----------+
My (not correct) query:
-- This query is not right, it returns a row for each nephew
select parent_name, nephew_name
from parent p
left outer join parent_nephew_link pnl
on p.parent_id = pnl.parent_id
left outer join nephew n
on n.nephew_id = pnl.nephew_id
where enabled = 1
-- I wish I could add this clause to restrict the result to the oldest
-- nephew but p.parent_id is not available in sub-selects.
-- You get an ORA-00904 error if you try this:
-- and n.birthday = (select min(birthday) from nephew nested where nested.parent_id = p.parent_id)
My desired output would be:
+-------------+-------------+
| parent_name | nephew_name |
+-------------+-------------+
| Donald | Louie |
+-------------+-------------+
| Mickey | Ferdie |
+-------------+-------------+
Thanks for any advice!
John
markaaronky's suggestion
I tried using markaaronky's suggestion but this sql is also flawed.
-- This query is not right either, it returns the correct data but only for one parent
select * from (
select parent_name, n.nephew_name, n.birthday
from parent p
left outer join parent_nephew_link pnl
on p.parent_id = pnl.parent_id
left outer join nephew n
on n.nephew_id = pnl.nephew_id
where enabled = 1
order by parent_name, n.birthday asc
) where rownum <= 1

Answer 1

Why not:
(1) include the n.birthday from the nephews table in your SELECT statement
(2) add an ORDER BY n.birthday ASC to your query
(3) also modify your select so that it only takes the top row?
I tried to write this out in sqlfiddle for you but it doesn't seem to like table aliases (e.g. it throws an error when I write n.birthday), but I'm sure that's legal in Oracle, even though I'm a SQL Server guy.
Also, if I recall correctly, Oracle doesn't have a SELECT TOP like SQL Server does... you have to do something like "WHERE ROWNUM = 1" instead? Same concept... you're just ordering your results so the oldest nephew is the first row, and you're only taking the first row.
Perhaps an undesired side effect is you WOULD get the birthday along with the names in your results. If that's unacceptable, my apologies. It looked like your question has been sitting unanswered for a while and this solution should at least give you a start.
Lastly, since you don't have a NOT NULL constraint on your birthday column and are doing left outer joins, you might make the query safer by adding AND n.birthday IS NOT NULL

Answer 2

Use:
select parent_name, nephew_name
from parent p
left outer join
(
SELECT pnl.parent_id, n.nephew_name
FROM parent_nephew_link pnl
join nephew n
on n.nephew_id = pnl.nephew_id
AND n.BIRTHDAY = (
SELECT min( BIRTHDAY )
FROM nephew n1
JOIN parent_nephew_link pnl1
ON pnl1.NEPHEW_ID = n1.NEPHEW_ID
WHERE pnl1.PARENT_ID = pnl.PARENT_ID
)
) ppp
on p.parent_id = ppp.parent_id
where p.enabled = 1
Demo: http://sqlfiddle.com/#!4/98758/23
| PARENT_NAME | NEPHEW_NAME |
|-------------|-------------|
| Mickey | Louie |
| Donald | Ferdie |