title: GROUP BY day but for specific timestamp
body: <p>I want to group by day but time shouldn't be 00:00:00 to 23:59:59
  It should be 22:00:00 (previuos day) to 21:59:59 (current day)</p>
  
  <p>I have query:</p>
  
  <pre><code>SELECT
      DATE_TRUNC('day',"timecolumn") "DATE",
      COUNT(*) 
  FROM "schemaname"."tablename"
  WHERE
      TO_CHAR("timecolumn",'YYYYMMDD') BETWEEN '20200301' AND '20200307'
  GROUP BY "DATE";
  </code></pre>
  
  <p>This is giving me count split across 7 days.</p>
  
  <p><strong>But this data is calculated as below:</strong></p>
  
  <pre><code>2020-03-01 00:00:00 to 2020-03-01 23:59:59
  2020-03-02 00:00:00 to 2020-03-02 23:59:59
  2020-03-03 00:00:00 to 2020-03-03 23:59:59
  2020-03-04 00:00:00 to 2020-03-04 23:59:59
  2020-03-05 00:00:00 to 2020-03-05 23:59:59
  2020-03-06 00:00:00 to 2020-03-06 23:59:59
  2020-03-07 00:00:00 to 2020-03-07 23:59:59
  </code></pre>
  
  <p><strong>Whereas, I need data split across as below:</strong></p>
  
  <pre><code>2020-02-29 22:00:00 to 2020-03-01 21:59:59
  2020-03-01 22:00:00 to 2020-03-02 21:59:59
  2020-03-02 22:00:00 to 2020-03-03 21:59:59
  2020-03-03 22:00:00 to 2020-03-04 21:59:59
  2020-03-04 22:00:00 to 2020-03-05 21:59:59
  2020-03-05 22:00:00 to 2020-03-06 21:59:59
  2020-03-06 22:00:00 to 2020-03-07 21:59:59
  </code></pre>