title: SQL - How to append a period
body: <p>I have an existing SQLite_table like this:</p>
  <pre><code>startdate  -   enddate
  2018-01-01  -  2018-06-30
  2018-07-01  -  2018-12-31
  2019-01-01  -  2019-06-30
  2019-07-01  -  2019-12-31
  2020-01-01  -  2020-06-30
  2020-07-01  -  2020-12-31
  2021-01-01   - 2021-06-30
  </code></pre>
  <p>What is the SQL-Statement for the result;
  The result should be:</p>
  <pre><code>2019-11-01  2020-12-31  // 60  Days difference
  2020-01-01  2020-06-30  // 180 Days difference
  2020-07-01  2020-12-31  // 180 Days difference
  2021-01-01  2021-06-30  // 180 Days difference
  </code></pre>
  <p><code>'2019-11-01'</code> is entered via the search field in my Android app as input
  The point is the output of the small period at the beginning / the
  insertion of the first period in the statement
  I tried 'Union' and it gives me an error.</p>
  <p>How can I do this with a query ?</p>
  <p>I am thankful for any help</p>
  <p>and what is the SQL statement, when it should
  return data from '2019-11-01' until 'now'</p>
  <pre><code>2019-11-01  2020-12-31  // 60  Days difference
  2020-01-01  2020-06-30  // 180 Days difference
  2020-07-01  2020-12-31  // 180 Days difference
  2021-01-01  2021-02-16  // 46 Days difference ! ! 
  </code></pre>
  <p>Thank's</p>