MySQL: Grouped primary key with InnoDB

Question

Is there an equivalent to a grouped primary key using an InnoDB MySQL database and allowing auto-increment on the second key?

What I am trying to implement is a table to

Answer 1

there can be only one auto column and it must be defined as a key. check this

CREATE TABLE images (
   parent_id INT(11) NOT NULL,
   image_id INT(11) Not Null  AUTO_INCREMENT, 
   source_url VARCHAR(255) NOT NULL,
   caption VARCHAR(255) NOT NULL,

   key(image_id),                          -- add as a key       
   PRIMARY KEY(parent_id, image_id)
) ENGINE = InnoDB;