DELIMITER //
CREATE PROCEDURE time_convert (IN time_server DATETIME, OUT time_client DATETIME) BEGIN
DECLARE timezone INT;
SET timezone=3;
IF(timezone>0 OR timezone=0)THEN
SET time_client=convert_tz(time_server,@@session.time_zone,CONCAT('+',timezone,':00'));
ELSE
SET time_client=convert_tz(time_server,@@session.time_zone,CONCAT(timezone,':00'));
END IF;
END