Question

我会创建这个表。

create table Books 
  (
  book_id number PRIMARY KEY,
  Title number,
  yearpub DATE,
  author_id number
  )

create table Authors 
  (
  author_id number,
  book_id number
  )  

create table Author_name 
  (
  author_id number,
  first_name varchar(10),
  last_name varchar(10)
  )

我现在没有安装Oracle，但我想选择每位作者的第一本书和最后一本书之间的日期差异（年数）我认为应该有一些集合功能。

Answer 1

SELECT authors.author_id,
       max(name.first_name||' '||name.last_name) as full_name,
       max(to_char(yearpub,'yyyy')) - min(to_char(yearpub,'yyyy')) as  years
from author_name name, books,authors
where
      authors.author_id = name.author_id and
      authors.author_id = books.author_id and
      authors.book_id = books.book_id
group by authors.author_id

每位作者的第一本书和最后一本书的日期差异

1 个答案: