Select 最高值链接到标题 - sql

Question

I am trying to select the highest pair from a table that has been created by joining (combining) two tables. I guess I should use a nested query but I'm not sure how. I also came around a similar question that seems a bit less complex, but I am struggling to implement it into my problem.

Similar question: How to select max timestamp from each currency pair SQL?

My tables:

Book:

title	publisher	price	sold
book1	A	5	300
book2	B	15	150
book3	A	8	350

Publisher:

code	name
A	ABook
B	BBook
C	CBook

My query:

SELECT b.titel, p.name, max(b.price*b.sold) as 'Revenue"
FROM publisher p, book b
WHERE p.code = b.publisher

Gives:

title	publisher	Revenue
book1	ABook	1500
book2	BBook	2250
book3	ABook	2800

Desired output:

title	publisher
book2	BBook
book3	ABook

How to alter my query to get the highest revenue per book title and the corresponding publisher?

Answer 1

You can use this query:

SELECT b.titel, p.name FROM publisher p, book b WHERE p.code = b.publisher order by b.price*b.sold desc

Answer 2

You can use row_number window function to select the appropriate row for each group.

Your desired results don't align with your description (do you want a revenue column or not?), however this produces your desired output. Note the use of modern (for 30 years) ansi join syntax:

with sold as (
    select *, Row_Number() over(partition by publisher order by (price * sold) desc) rn
    from book b join publisher p on p.code=b.publisher
)
select title, name Publusher
from sold
where rn=1

Answer 3

I solved it by using a nested query (I guess?)

select b.title, p.name
from boek b join publisher p on p.code = b.publisher
where b.sold*b.price = (select max(sold*price)
                     from book t2
                     where t2.publisher = b.publisher
                    )