Shulou(Shulou.com)05/31 Report--

Today, I will talk to you about how to delete duplicate lines in mysql. Many people may not know much about it. In order to make you understand better, the editor has summarized the following content for you. I hope you can get something according to this article.

Table relation

Create table relation (id int primary key auto_increment, userId int not null, fanId int not null)

Insert several pieces of data

Insert into relation (userId,fanId) values (1), (1), (1), (2), (2), (3), (3)

Data in the table

IduserIdfanId111211311422522633733

Deweighting

Delete t from relation sjoin relation t using (userId,fanId) where s.id

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