how to remove duplicate rows in mysql with using temporary table

after i get 100 Million of url’s, i saw a few of duplicates on my mysql table. I used the command line because the MySQL Workbench was not usable with minimum system resources.

For login on Terminal on Mac OS X with MySQL Community Server version: 8.0.29 – GPL

mysql -u root -p 

after this command, u need to log in with your password. Don’t forget to change the current database.

use tablename;

Best-Case duplicate removing via temporary table:

create table tmp like urls;
alter table tmp add unique (url);
insert into tmp select * from tablename.urls on duplicate key update domainname=ifnull(urls.domainname, values(domainname));

example table for used command:

id | url | domainname
1 | | google
2 | |  yahoo
3 | |  delalo

I get following response for my query with deleted 36.271 duplicate in 40 minutes.

Query OK, 77017135 rows affected, 1 warning (40 min 23,60 sec)
Records: 96424261  Duplicates: 36271  Warnings: 1

example search queries for search engines:

how to remove duplicate rows in mysql with using temporary table

Query for removing duplicates rows in temp table

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