title: How to search in sqlite for hour regardless of timezone?
body: <p>I wanted to make a database containing my blood sugar levels (I have diabetes). 
  For each entry, the timestamp of the measurement is saved like this "2020-05-02 12:11:13 +0200".</p>
  
  <p>Now I want to plot the data by the hour (get the same hour of different days). </p>
  
  <p>If I have traveled to a different timezone the entries for this day will be n hours of.
  For example, if I want to get all entries for 13:00 I will get the values that were measured at 04:00 in California and 20:00 in Tokyo. But I want the 13:00 o'Clock values from all these places/timezones.</p>
  
  <p>Is this possible, or should I just create a separate column for UTC and local time?  </p>
  
  <p>I already tried things like these: </p>
  
  <pre><code>... WHERE strftime('%H', date) = '13'
  ... WHERE strftime('%H', date,"UTC") = '13'
  ... WHERE time(date)&gt;= time('00:00:00','+13 hour')
  </code></pre>
  
  <p><strong>Solution:</strong>
  See @forpas answer.</p>
  
  <p>I modified it a little </p>
  
  <pre><code>strftime('%H',datetime( substr(date, 1, 19))) = '10'
  </code></pre>