Detailed description of the auto-incrementing primary key ID re-sorting method in Mysql

Generally, if we use the ID auto-incrementing primary key and delete the key, we cannot simply rank the ID again. Here are some operation tips.

The IDS of the auto-incrementing primary keys in Mysql database tables are messy and need to be rearranged.

Principle: Delete the original auto-increment ID and create a new auto-increment ID.

1. Delete the original primary key:

The Code is as follows:	Copy code
Alter table 'table _ name' DROP 'id ';

2. Add the new primary key field:

The Code is as follows:	Copy code
Alter table 'table _ name' add'id' MEDIUMINT (8) not null first;

3. Set the new primary key:

The Code is as follows:	Copy code
Alter table 'table _ name' modify column 'id' MEDIUMINT (8) not null AUTO_INCREMENT, add primary key (id );

Another way is to use php to re-create a data record. When deleting data, you only need to add the delete mark. If you do not delete the data record, you can.