title: T-SQL Add new column in existing table and fill with value from two another existing column
body: <p>I have a table <code>test</code> with the following columns: <code>id</code>, <code>startDate</code>, <code>stopDate</code>, <code>startOvertime</code>, <code>stopOvertime</code>.</p>
  
  <p><code>startDate</code> and <code>stopDate</code> are of type datetime and <code>startOvertime</code>, <code>stopOvertime</code> are of type <code>time(7)</code>.</p>
  
  <p>I want to create a new column with the date portion from <code>stopDate</code> and the time portion from <code>startOvertime</code> and copy that into a newly created column <code>test-fill</code>.</p>
  
  <p>If I use formula (stopDate, startOvertime) then the value of the new datetime column is not right. Any proposals?</p>