Mysql modifies the method of adding primary keys

This article mainly introduces the method of modifying and adding primary keys to mysql, which is very detailed and has certain reference value. Friends who are interested must finish reading it!

Mysql modifies the method of adding a primary key: execute [ALTER TABLE `test2` DROP PRIMARY KEY, ADD PRIMARY KEY (`id`);] statement to modify the primary key.

Add table field

Alter table table1 add transactor varchar (10) not Null;alter table table1 add id int unsigned not Null auto_increment primary key

Modify primary key

ALTER TABLE `test2` DROP PRIMARY KEY, ADD PRIMARY KEY (`id`)

Add index

ALTER TABLE `test2` ADD INDEX (`id`) ALTER TABLE `category `MODIFY COLUMN `id` int (11) NOT NULL AUTO_INCREMENT FIRST, ADD PRIMARY KEY (`id`). These are all the contents of mysql's method of modifying and adding primary keys. Thank you for reading! Hope to share the content to help you, more related knowledge, welcome to follow the industry information channel!