DELIMITER $$
DROP PROCEDURE IF EXISTS SetVisitorStat$$
CREATE PROCEDURE SetVisitorStat(
         IN in_ip VARCHAR(15),
                                   in_host VARCHAR(250),
                                   in_referrer VARCHAR(250),
                                   in_agent VARCHAR(250),
                                   in_user_uid MEDIUMINT(8)
        )
BEGIN

DECLARE var_host MEDIUMINT DEFAULT 0;
DECLARE var_referrer MEDIUMINT DEFAULT 0;
DECLARE var_ip MEDIUMINT DEFAULT 0;
DECLARE var_agent MEDIUMINT DEFAULT 0;

SELECT `uid` INTO var_host
FROM `stat_host` WHERE `stat_host`.`host` = in_host;
IF var_host = 0 THEN
INSERT INTO `stat_host` (`host`)
VALUES (in_host);
SELECT LAST_INSERT_ID() INTO var_host;
END IF;

SELECT `uid` INTO var_referrer
FROM `stat_referrer` WHERE `stat_referrer`.`referrer` = in_referrer;
IF var_referrer = 0 THEN
INSERT INTO `stat_referrer` (`referrer`)
VALUES (in_referrer);
SELECT LAST_INSERT_ID() INTO var_referrer;
END IF;

SELECT `uid` INTO var_ip
FROM `stat_ip` WHERE `stat_ip`.`ip` = in_ip;
IF var_ip = 0 THEN
INSERT INTO `stat_ip` (`ip`)
VALUES (in_ip);
SELECT LAST_INSERT_ID() INTO var_ip;
END IF;

SELECT `uid` INTO var_agent
FROM `stat_agent` WHERE `stat_agent`.`agent` = in_agent;
IF var_agent = 0 THEN
INSERT INTO `stat_agent` (`agent`)
VALUES (in_agent);
SELECT LAST_INSERT_ID() INTO var_agent;
END IF;

INSERT INTO `stat_visiting` (`time`, `ip_uid`, `host_uid`,
         `referrer_uid`,  `agent_uid`, `user_uid`)
VALUES (NOW(), var_ip, var_host, var_referrer, var_agent, in_user_uid);

END$$

DELIMITER ;

-- CALL SetVisitorStat('111', '222', '333', '444', '555');

mysql_connect("localhost", "mysql_user", "mysql_password");
mysql_select_db("mydb");

mysql_query("CALL SetVisitorStat('192.168.19.03', 'www.test.ua', 'www.google.com.ua', 'Google Chrome 2.0', '42');");