I can not just join it because I need to group DVDs by movie_id first? - ORACLE - oracle11g

Question

I have this query that has no problem:
SELECT m.movie_name, cd.times_requested
FROM movie m,
(select *
from(
select movie_id, count(movie_id) as times_requested
from movie_queue
where status_id=0 or status_id=1
group by movie_id
) ab
where times_requested>1) cd
WHERE m.movie_id=cd.movie_id;
It returns the following list.
MOVIE_NAME TIMES_REQUESTED
----------------------------------------------------------------------
E.T. the Extra-Terrestrial 2
Indiana Jones and the Kingdom of the Crystal Skull 2
War of the Worlds 3
Unbreakable 3
Question:
How do I add another column showing the amount of DVDs available for each movie, I can not just join it because I need to group DVDs by movie_id first?.
Table above is OK, but I want to add a third column, the third column will contain information about the number of DVDs available for each movie. the problem is that the number of dvds is stored in another table call DVDS. The structure of the table DVDs is similar to this:
DVD_ID MOVIE_ID DVD_ENTRY_DATE
---------- ---------- --------------
1 1 24-JUL-12
2 1 24-JUL-12
3 1 24-JUL-12
4 2 24-JUL-12
5 2 24-JUL-12
Desired Result:
Final table should look similar to the one below:
MOVIE_NAME TIMES_REQUESTED DVDS_AVAILABLE
-------------------------------------------------------------------
E.T. the Extra-Terrestrial 2 3
Indiana Jones and the Kingdom 2 1
War of the Worlds 3 3
Unbreakable 3 1
I tried the following code, but did not get the result I wanted
I am assuming I need to go to dvd table first and find all dvds that match the movie_id I want and group them by movie_id. I tried the code below, but instead of returning the 4 rows I want it is returning 72.
SELECT m.movie_name, pomid.times_requested, d.dvds_available
FROM movie m,
(select *
from(
select movie_id, count(movie_id) as times_requested
from movie_queue
where status_id=0 or status_id=1
group by movie_id
) mid
where times_requested>1) pomid,
(select movie_id, count(movie_id) as dvds_available
from dvd
group by movie_id) d
WHERE m.movie_id=pomid.movie_id;
Thanks for your suggestions in how to fix this.

Answer 1

A join to d.movie_id is missing, that's why you get too many rows. (Quick check: how many tables do I have? How many joins do I have?)
And I'd also add an outer join to get all movies, even when there are no dvd or movie_queue entries.
SELECT m.movie_name
,NVL(pomid.times_requested,0) times_requested
,NVL(d.dvds_available,0) dvds_available
FROM movie m
,(SELECT *
FROM (SELECT movie_id
,COUNT (movie_id) AS times_requested
FROM movie_queue
WHERE status_id = 0
OR status_id = 1
GROUP BY movie_id) mid
WHERE times_requested > 1) pomid
,(SELECT movie_id
,COUNT (movie_id) AS dvds_available
FROM dvd
GROUP BY movie_id) d
WHERE m.movie_id = pomid.movie_id(+)
AND d.movie_id(+) = pomid.movie_id;
http://www.sqlfiddle.com/#!4/5437a/11

Answer 2

Not sure I really understand your table structure, but this might get you started:
select movie_id,
sum(case when status_id in (0,1) then 1 else 0 end) as times_requested,
count(movie_id) as dvd_available,
from movie_queue
group by movie_id;