MySQL self-add primary Key ID reordering method detailed

The MySQL database table's self-added primary key ID number is messed up and needs to be rearranged.

Principle: Remove the original ID and re-establish the new self ID.

1, delete the original primary key:

The code is as follows	Copy Code
ALTER TABLE ' table_name ' DROP ' ID ';

2, add a new primary key field:

The code is as follows	Copy Code
ALTER TABLE ' table_name ' ADD ' ID ' mediumint (8) Not NULL-I;

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 once, delete the data with only the deletion tag, do not really delete data records on it.