title: MySQL Partitioning. The partition function return wrong type
body: <p>What is incorrect in the following query?</p>
  
  <pre><code>CREATE TABLE `tbl_user_geolocation` (
              `id` INT(11) NOT NULL AUTO_INCREMENT COMMENT 'Идентификатор',
              `user_id` VARCHAR(100) NOT NULL COMMENT 'ID пользователя',
              `client_type` VARCHAR(38) NULL DEFAULT NULL COMMENT 'Тип клиента',
              `lat` DECIMAL(28,8) NOT NULL COMMENT 'Широта',
              `lon` DECIMAL(28,8) NOT NULL COMMENT 'Долгота',
              `created_at` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT 'Дата создания',
              PRIMARY KEY (`id`, `user_id`)
          )
          PARTITION BY HASH(id+user_id) PARTITIONS 200;
  </code></pre>
  
  <p>Error: The partition function returns the wrong type. 1491.
  This table using for save users geo-location data </p>