How can I exclude LEFT JOINed tables from TOP in SQL Server? - sql-server

Question

Let's say I have two tables of books and two tables of their corresponding editions.
I have a query as follows:
SELECT TOP 10 * FROM
(SELECT hbID, hbTitle, hbPublisherID, hbPublishDate, hbedID, hbedDate
FROM hardback
LEFT JOIN hardbackEdition on hbID = hbedID
UNION
SELECT pbID, pbTitle, pbPublisher, pbPublishDate, pbedID, pbedDate
FROM paperback
Left JOIN paperbackEdition on pbID = pbedID
) books
WHERE hbPublisherID = 7
ORDER BY hbPublishDate DESC
If there are 5 editions of the first two hardback and/or paperback books, this query only returns two books. However, I want the TOP 10 to apply only to the number of actual book records returned. Is there a way I can select 10 actual books, and still get all of their associated edition records?
In case it's relevant, I do not have database permissions to CREATE and DROP temporary tables.
Thanks for reading!
Update
To clarify: The paperback table has an associated table of paperback editions. The hardback table has an associated table of hardback editions. The hardback and paperback tables are not related to each other except to the user who will (hopefully!) see them displayed together.

Answer 1

If I understand you correctly, you could get the 10 books with all associated editions by
Using a WITH statement to return the initial, complete resultset
select 10 distinct books by using a GROUP BY
JOIN the results of this group to retain all information from given 10 books.
SQL Statement
;WITH books AS (
SELECT hbID, hbTitle, hbPublisherID, hbPublishDate, hbedID, hbedDate
FROM hardback
LEFT JOIN hardbackEdition on hbID = hbedID
WHERE hbPublisherID = 7
UNION ALL
SELECT pbID, pbTitle, pbPublisher, pbPublishDate, pbedID, pbedDate
FROM paperback
LEFT JOIN paperbackEdition on pbID = pbedID
WHERE hbPublisherID = 7
)
SELECT *
FROM books b
INNER JOIN (
SELECT TOP 10 hbID
FROM books
GROUP BY
hbID
) bt ON bt.hbID = b.hbID
or if you prefer to write the where clause only once
;WITH books AS (
SELECT hbID, hbTitle, hbPublisherID, hbPublishDate, hbedID, hbedDate
FROM hardback
LEFT JOIN hardbackEdition on hbID = hbedID
UNION ALL
SELECT pbID, pbTitle, pbPublisher, pbPublishDate, pbedID, pbedDate
FROM paperback
LEFT JOIN paperbackEdition on pbID = pbedID
)
, q AS (
SELECT *
FROM books
WHERE hbPublisherID = 7
)
SELECT *
FROM q b
INNER JOIN (
SELECT TOP 10 hbID
FROM q
GROUP BY
hbID
) bt ON bt.hbID = b.hbID

Answer 2

Not so easy. You need to apply Top 10 to only the hardback and paperback tables, without the join. Then join the result to the data.
The following query only works when the hbID and pbID are always unique. If not, it gets more complicated. You need to separate them or add another column to the query to distinguish them.
SELECT *
FROM
(SELECT hbID as id, hbTitle, hbPublisherID, hbPublishDate, hbedID, hbedDate
FROM hardback
LEFT JOIN hardbackEdition on hbID = hbedID
UNION
SELECT pbID as id, pbTitle, pbPublisher, pbPublishDate, pbedID, pbedDate
FROM paperback
Left JOIN paperbackEdition on pbID = pbedID
) books
INNER JOIN
(SELECT TOP 10 *
FROM
(SELECT hbID as id, hbPublisherID as publishedId, hbPublishDate as publishDate
FROM hardback
UNION
SELECT pbID as id, pbPublisherID as publishedId, pbPublishDate as publishDate
FROM paperback
)
WHERE publisherID = 7
ORDER BY publishDate DESC
) topTen
on books.id = TopTen.id

Answer 3

This should grab the ten most recently published titles with a hardback from publisher 7:
select *
from (
select top 10 title
from hardback
where hbPublisherID = 7
group by
title
order by
hbPublishDate desc
) top_titles
left join
hardback
on hardback.hbTitle = top_titles.title
left join
paperback
on paperback.pbTitle = top_titles.title