如何根据条件合并 2 个表但 select 值？

Question

有 2 tables - 书籍，用品。供应 table:

supply_id	title	author	price	amount
1	title1	author1	518.99	2
2	title2	author2	570.20	6
3	title3	author3	540.50	7
4	title4	author4	360.80	3

这本书 table:

book_id	title	author	price	amount
1	Мастер и Маргарита	Булгаков М.А.	670.99	3
2	Белая гвардия	Булгаков М.А.	540.50	5
3	Идиот	Достоевский Ф.М.	460.00	10
4	Братья Карамазовы	Достоевский Ф.М.	799.01	3
5	Игрок	Достоевский Ф.М.	480.50	10
6	Стихотворения и поэмы	Есенин С.А.	650.00	15

我需要合并它们，但只有 select 那些价格较高的行。

select title, price, amount 
from supply  a1
union all
select title, price, amount 
from book a2
where a1.price > a2.price

Answer 1

您可以使用 window 函数：

select bs.*
from (select bs.*,
             row_number() over (partition by title order by price desc) as seqnum
      from ((select supply_id, title, author, price, amount
             from book
            ) union all
            (select supply_id, title, author, price, amount
             from supply
            )
           ) bs
     ) bs
where seqnum = 1;

Answer 2

试试这个：

select title, price, amount 
from supply s
where not exists (select 1 from book b where s.title = b.title and b.price > s.price)

union all

select title, price, amount 
from book b
where not exists (select 1 from supply s where s.title = b.title and s.price > b.price)

如何根据条件合并 2 个表但 select 值？

how to union 2 tables but select values based on condition?

mysql

sql

union-all