title: MySQL SUM returns wrong value
body: <p>If I add a table like this in MySQL:</p>
  
  <pre><code>CREATE TABLE `test` (
    `id` int(11) NOT NULL AUTO_INCREMENT,
    `value` float NOT NULL,
    PRIMARY KEY (`id`)
  );
  </code></pre>
  
  <p>and add an entry:</p>
  
  <pre><code>INSERT INTO `test` (`value`) VALUES ('123.45');
  </code></pre>
  
  <p>and do a SUM on it like this:</p>
  
  <pre><code>SELECT SUM( value )
  FROM `test` 
  </code></pre>
  
  <p>why does it return 123.449996948242 and not 123.45?</p>