Question

我有两张桌子：

connections
id | publisherId | authorId

和

books
id | connectionId | title

我想合并这些表只能得到一个表：

books
id| publisherId | authorId | title

如何只使用一个SQL查询？

Answer 1

CREATE TABLE newtable
SELECT b.id, c.publisherId, c.authorID, b.title
FROM books b
INNER JOIN connections c
on c.id = b.connectionId

未经测试，但应该这样做。我假设你想要书籍表中的ID，否则你需要c.id而不是b.id。

然后你可以删除旧表并将其重命名为你想要的任何内容。

Answer 2

CREATE TABLE connections_books 
SELECT books.id as id, 
       connections.publisherId as publisherId, 
       connections.authorId as authorId, 
       books.title as title 
FROM books join connections on books.connectionId = connections.id;

首先仅使用select部分测试查询：

SELECT books.id as id, 
       connections.publisherId as publisherId, 
       connections.authorId as authorId, 
       books.title as title 
FROM books join connections on books.connectionId = connections.id;

一旦这给你你想要的东西，继续创建表。

确保新表中的列名称正确非常重要。使用select语句测试确保您的列名称符合您的要求。如果要更改列名称，请更改所选每列的as ...名称。

更改数据库结构：需要SQL查询

2 个答案: