DROP FUNCTION IF EXISTS `__mydiv`;
DELIMITER $$
CREATE DEFINER=`root`@`127.0.0.1` FUNCTION `__mydiv`(`a` int, `b` int) RETURNS bigint(20)
BEGIN
# Copyright (C) 2009-2011 Mohammad Saleh Souzanchi
# WebLog : http://www.saleh.soozanchi.ir
# Version V1.0.2

return FLOOR(a / b);
END;;
DELIMITER ;

SQL query:

DELIMITER ; ;

CREATE DEFINER = `root`@`127.0.0.1` FUNCTION `__mydiv` (
`a` int,
`b` int
) RETURNS bigint( 20 ) BEGIN # Copyright (C) 2009-2011 Mohammad Saleh Souzanchi
# WebLog : http://www.saleh.soozanchi.ir
# Version V1.0.2
RETURN FLOOR( a / b ) ;

END ; ;

MySQL said: Documentation
#1418 – This function has none of DETERMINISTIC, NO SQL, or READS SQL DATA in its declaration and binary logging is enabled (you *might* want to use the less safe log_bin_trust_function_creators variable)