Wrong data type for CREATE..SELECT year_sp_variable

DROP PROCEDURE IF EXISTS p1;

DELIMITER $$

CREATE PROCEDURE p1()

BEGIN

  DECLARE a YEAR;

  CREATE OR REPLACE TABLE t1 AS SELECT a;

  SHOW CREATE TABLE t1;

  DROP TABLE t1;

END;

$$

DELIMITER ;

CALL p1;

+-------+-----------------------------------------------------------------------------------------------+

| Table | Create Table                                                                                  |

+-------+-----------------------------------------------------------------------------------------------+

| t1    | CREATE TABLE `t1` (

  `a` int(4) unsigned DEFAULT NULL

) ENGINE=InnoDB DEFAULT CHARSET=latin1 |

+-------+-----------------------------------------------------------------------------------------------+