title: SQLite group by/count hours, days, weeks, year
body: <p>Assume that we have a simple Android application that has only one button.<br/>
  Click on that button record the date and time of that click (in sqlite).<br/>
  I wondering what is the best format for that records keep a long or a string of that date-time.<br/>
  The purpose is to make reports that show:<br/>
  1. sum of clicks that made for chosen day grouped by hours.<br/>
  2. sum of clicks that made for chosen week grouped by days.<br/>
  3. sum of clicks that made for chosen month grouped by weeks.<br/>
  4. sum of clicks that made for chosen year grouped by month.<br/></p>
  
  <p>How to create such database and how do I do such queries?</p>