SET AUTOCOMMIT=0;
USE kamailio;

INSERT INTO usr_preferences (uuid,username,domain,attribute,type,value,last_modified)
SELECT uuid,username,domain,'reseller_id',type,(
    SELECT reseller_id FROM billing.contracts LEFT JOIN billing.contacts on billing.contacts.id=billing.contracts.contact_id
        WHERE billing.contracts.id=value
    ),now() FROM usr_preferences WHERE attribute='account_id';

COMMIT;