title: How to convert MySQL Datetime UMT to actual Timezone
body: <p>I have a database which stores datetime from GPS Trackers in UTC format.
  For example something like:</p>
  
  <pre><code>CREATE TABLE IF NOT EXISTS `tab_data` (
    `id` int(6) unsigned NOT NULL,
    `utc_time` varchar(200) NOT NULL,
    PRIMARY KEY (`id`)
  ) DEFAULT CHARSET=utf8;
  INSERT INTO `tab_data` (`id`, `utc_time`) VALUES
    ('1', '2018-01-05 07:00:00'), //this should be in UTC +1
    ('2', '2018-02-04 01:10:00'), //this should be in UTC +1
    ('3', '2018-07-01 15:00:00'), //this should be in UTC +2
    ('4', '2018-08-22 16:00:00'); //this should be in UTC +2
  </code></pre>
  
  <p>What I want to do is to get this data from database in proper time for Poland.
  In Poland like in many countries in Europe we have a summer and winter time:
  - winter is a CET time zone (UTC+1)
  - summer is a CEST time zone (UTC+2)</p>
  
  <p>How to get this DateTime from database converted to proper time (+1 or +2h)</p>
  
  <p>Normally I will use this query, but this time must be converted to the time zone applicable at the appropriate time of the year</p>
  
  <pre><code>SELECT `utc_time` AS time FROM `tab_data`;
  </code></pre>
  
  <p>I know that it is the option CONVERT_TZ, but as per as know I can only convert this from one timezone to other, not from two different time zones.</p>
  
  <p>Here is SQL Fiddle
  <a href="http://sqlfiddle.com/#!9/a09700/2" rel="nofollow noreferrer">http://sqlfiddle.com/#!9/a09700/2</a></p>
  
  <p>If this is hard to do in MySQL I could also make it in PHP</p>