InnoDB: Strange printed result on SELECT DISTINCT col_bit ... ORDER BY col_bit

CREATE TABLE `t_innodb` ( `pk` int(11) NOT NULL, `col_bit` bit(29) NOT NULL DEFAULT b'0',  PRIMARY KEY (`pk`))  ENGINE = InnoDB DEFAULT CHARSET=latin1;

CREATE TABLE `t_myisam` ( `pk` int(11) NOT NULL, `col_bit` bit(29) NOT NULL DEFAULT b'0',  PRIMARY KEY (`pk`))  ENGINE = MyISAM DEFAULT CHARSET=latin1;

INSERT INTO `t_innodb` ( `pk` ) VALUES ( 38502 ) ;

INSERT INTO t_myisam SELECT * FROM t_innodb;

SELECT `col_bit` FROM `t_innodb`;

col_bit

                  <= I guess the value is just not printable like in several other cases below.

SELECT `col_bit` FROM `t_myisam`;

col_bit

SELECT `col_bit` FROM `t_innodb` ORDER BY `col_bit`;

col_bit

SELECT `col_bit` FROM `t_myisam` ORDER BY `col_bit`;

col_bit

SELECT DISTINCT `col_bit` FROM `t_innodb` ORDER BY `pk`;

col_bit

SELECT DISTINCT `col_bit` FROM `t_myisam` ORDER BY `pk`;

col_bit

SELECT DISTINCT `col_bit` FROM `t_innodb` ORDER BY `col_bit`;

col_bit

0                     <== Why that?

SELECT DISTINCT `col_bit` FROM `t_myisam` ORDER BY `col_bit`;

col_bit

CREATE TABLE t_aux AS SELECT DISTINCT `col_bit` FROM `t_innodb` ORDER BY `pk`;

SHOW CREATE TABLE t_aux;

Table   Create Table

t_aux   CREATE TABLE `t_aux` (

  `col_bit` bit(29) NOT NULL DEFAULT b'0'

) ENGINE=MyISAM DEFAULT CHARSET=latin1

SELECT * FROM t_aux;

col_bit

SELECT pk, col_bit FROM t_innodb INNER JOIN t_myisam USING (pk, col_bit);

pk      col_bit

38502                <==  This looks reasonable.

DROP TABLE t_innodb;

DROP TABLE t_myisam;

DROP TABLE t_aux;