Here are some useful MYSQL functions:

	
		DROP FUNCTION randpasswd;
		DELIMITER //
		CREATE FUNCTION randpasswd(n INT) returns VARCHAR(255) READS SQL DATA
		BEGIN
		DECLARE passwd VARCHAR(255);
		SET passwd='';
		WHILE LENGTH(passwd)<n DO
			SELECT CONCAT(
				passwd,
				substr('abcdefghijklmnopqrstuvwxyz0123456789', rand()*36,1)
			) INTO passwd;
		END WHILE;
		RETURN passwd;
		END;
		//
		DELIMITER ;
		select randpasswd(100);