Partition Linear Hast with function how expretion

[Eduardo Garcia]

Hi People

I want make a partition using a Lineas Hash, but i need use mu personal function how hash key, show my function and my create table and error

--- Function ---
CREATE FUNCTION Get_Client_Creative (creative INT) RETURNS INT
BEGIN
DECLARE client INT;
SELECT P.client_id into client FROM Creative Cr,Adgroup Ag,Campaign Ca,Product P where Cr.adgroup_id=Ag.adgroup_id and Ag.campaign_id=Ca.campaign_id and P.Product_id=Ca.Product_id and creative_id=creative;
RETURN client;
END
//
---- Table -----
DROP TABLE IF EXISTS `Sid`;
CREATE TABLE `Sid` (
`sid_id` int(11) NOT NULL auto_increment,
`sid` varchar(255) NOT NULL default '',
`keyword_id` int(11) NOT NULL default '0',
`creative_id` int(11) NOT NULL default '0',
`sid2` varchar(255) NOT NULL default '',
`max_bid_cpc` double(5,2) unsigned NOT NULL default '0.00',
`min_cpc` double(5,2) unsigned NOT NULL default '0.00',
`parent_id` int(11) NOT NULL default '0',
`bid_percentage` double(5,2) NOT NULL default '1.00',
`status` varchar(50) NOT NULL default 'active',
PRIMARY KEY (`sid_id`),
KEY `keyword_id` (`keyword_id`),
KEY `creative_id` (`creative_id`),
KEY `sid2` (`sid2`),
KEY `sid` (`sid`),
KEY `parent_id` (`parent_id`)
)
PARTITION BY HASH( Get_Client_Creative(`creative_id`) )
PARTITIONS 50;

--- Error ----

ERROR 1064 (42000): Constant/Random expression in (sub)partitioning function is not allowed near ')
---------------

The function run ok, when im run in select how:

mysql> select * from User where user_id=Get_Client_Creative (250);


any help please, thanks for your reponses

enzo