CREATE PROCEDURE test_update()
BEGIN		
  UPDATE test_auto_inc ai
    JOIN test_join_limit jl ON jl.id = ai.id		
  SET ai.col_1  = null	
  LIMIT 500
  ;
END

-- table example 
CREATE TABLE `test_auto_inc` (  `
id` int unsigned NOT NULL AUTO_INCREMENT, 
 `col_1` int DEFAULT NULL, 
 PRIMARY KEY (`id`)) 
ENGINE=InnoDB AUTO_INCREMENT=8 DEFAULT CHARSET=utf8;

CREATE TABLE `test_join_limit` (  
`id` int(10) unsigned NOT NULL AUTO_INCREMENT,  
`col` int(10) DEFAULT NULL, 
 PRIMARY KEY (`id`)
)  ENGINE=InnoDB AUTO_INCREMENT=0 DEFAULT CHARSET=utf8;