title: how find the middle point between 2 dates in Sqlite
body: <p>I have these dates:</p>
  
  <p><code>"2019-01-01" and "2019-01-05"</code>
  ,I need this <code>"2019-01-03"</code></p>
  
  <p>How can I perform this on Sqlite?
  I tried <code>DateAdd(ms, DateDiff(ms, date1, date2), date1)/2</code> but this does not work in SQLite, this query given this error: <code>Result: no such column: ms
  </code></p>