MySQL: Change all given columns of a table from "int"'s to "timestamps"

changeIntToTimestamps.sql

DROP PROCEDURE IF EXISTS changeIntToTimestamps;
DELIMITER //
CREATE PROCEDURE changeIntToTimestamps(
	myschema		VARCHAR(255),
	colname		VARCHAR(255),
	autoUpdate	BOOL
)
	BEGIN
		DECLARE mytable VARCHAR(255);
		DECLARE col VARCHAR(255);
		DECLARE dtype VARCHAR(255);
		DECLARE mysql VARCHAR(255);
		DECLARE done INT default false;

		DECLARE allcols cursor for
		select
			c.TABLE_NAME,
			c.COLUMN_NAME,
			c.DATA_TYPE
		from
			INFORMATION_SCHEMA.COLUMNS c
		inner join INFORMATION_SCHEMA.TABLES t on
			c.TABLE_CATALOG = t.TABLE_CATALOG
			and c.TABLE_SCHEMA = t.TABLE_SCHEMA
			and c.TABLE_NAME = t.TABLE_NAME
		where
			c.DATA_TYPE like '%int%'
			and c.column_name like colname
			and c.TABLE_SCHEMA = myschema
		;
		DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = true;

		open allcols;

		fetch_loop: LOOP

			fetch next from allcols into mytable, col, dtype;

			if done then
				LEAVE fetch_loop;
			end if;

			set @mysql = CONCAT('alter table ', myschema, '.', mytable, ' CHANGE `', col, '` `', col, '` TIMESTAMP');

			if autoUpdate then
				set @mysql = CONCAT(@mysql, ' ON UPDATE CURRENT_TIMESTAMP NULL DEFAULT CURRENT_TIMESTAMP');
			else
				set @mysql = CONCAT(@mysql, ' NULL');
			end if;

			PREPARE statement from @mysql;

			SET @myschema = myschema;
			SET @mytable = mytable;
			SET @col = col;

			execute statement;
			DEALLOCATE PREPARE statement;
		end LOOP;

		close allcols;

		SELECT * FROM `information_schema`.`COLUMNS` WHERE `TABLE_SCHEMA` = myschema AND `COLUMN_NAME` LIKE colname;
	END
	//

DELIMITER ;

call changeIntToTimestamps( DATABASE(), 'created_on', false );