[英]How to copy column values to a new SQL table, remove duplicates and create mappings?
I have a table Excerpt
我有一张桌子Excerpt
CREATE TABLE IF NOT EXISTS excerpt(
excerptID INT UNSIGNED NOT NULL AUTO_INCREMENT,
author VARCHAR(45) NOT NULL,
title VARCHAR(255) NOT NULL,
text VARCHAR(2500) NOT NULL,
comments VARCHAR(2500) NOT NULL,
PRIMARY KEY (excerptID)
) ENGINE=INNODB CHARACTER SET utf8mb4;
and want to remove its column Author while distributing its (often duplicate) values and information about these values into two new tables Author
并希望在散发有关这些值的(通常复制)值和信息删除其列作者为两个新表Author
CREATE TABLE IF NOT EXISTS author(
authorID INT UNSIGNED NOT NULL AUTO_INCREMENT,
name VARCHAR(45) NOT NULL ,
PRIMARY KEY (authorID)
) ENGINE=INNODB CHARACTER SET utf8mb4;
and AuthorMap
:和AuthorMap
:
CREATE TABLE IF NOT EXISTS authormap (
excerptID INT UNSIGNED NOT NULL,
authorID INT UNSIGNED NOT NULL,
PRIMARY KEY (excerptID, authorID),
CONSTRAINT authorMapFK FOREIGN KEY (excerptID) REFERENCES excerpt (excerptID)
ON DELETE CASCADE
ON UPDATE CASCADE,
CONSTRAINT authorFK FOREIGN KEY (authorID) REFERENCES author (authorID)
ON DELETE CASCADE
ON UPDATE CASCADE
) ENGINE=INNODB;
All duplicates should be removed and mappings between excerptID and authorID placed into AuthorMap
, ie eventually all unique author names should be in the table Author
, their IDs created and all ExcerptID should be copied to AuthorMap
alongside with the newly created AuthorIDs.应删除所有重复项并将excerptID和authorID之间的映射放入AuthorMap
,即最终所有唯一的作者姓名都应在表Author
,创建的 ID 和所有ExcerptID应与新创建的 AuthorID 一起复制到AuthorMap
。
How should I do it?我该怎么做?
You can create the table authors
as:您可以将表authors
创建为:
create table authors (
author_id int auto_increment primary key,
name varchar(255) -- or whatever
);
insert into authors (name)
select distinct author
from excerpt;
Then create the author map table as:然后将作者映射表创建为:
create table excerptAuthors (
excerptAuthorsId int auto_icnrement primary key,
excerptid int,
authorid int
);
And finally:最后:
insert into excerptAuthors (excerptId, authorId)
select e.excerptId, a.authorId
from excerpts e join
authors a
on e.author = a.name;
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