Increment a primary key or delete a primary key from a table with an SQL statement

At the beginning of this demand, in the online search, found all said no, you have to delete the primary key column and then re-add or create a temporary table before the data, in fact, can be directly modified in MySQL.

Modify the ID field to self-increment the primary key:

ALTER TABLE ' Test ' change ' ID ' ' id ' int (one) UNSIGNED not NULL auto_increment, add primary key (' id ');

Modify ID field self-increment non-primary key:

ALTER TABLE ' Test ' change ' ID ' ' id ' int (one) UNSIGNED not NULL auto_increment, drop primary key;

Modify ID field to normal field:

ALTER TABLE ' Test ' change ' ID ' ' id ' int (one) UNSIGNED not NULL;

Increment a primary key or delete a primary key from a table with an SQL statement