title: How to merge columns in SQL of the same table
body: <p>I have two date columns.
  Sometimes they both have dates(Which will be same always in both the columns) and sometimes one is empty and one has date value.
  So, instead of two columns, I am trying to get one column.
  If one is empty it will take date value from other column and if both have values(which will always be same) it will just take any of the value from the two columns.</p>
  
  <p>I have tried UNION commands but its not giving me the desired result.</p>
  
  <p><a href="https://i.stack.imgur.com/aGnNU.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/aGnNU.png" alt="enter image description here"></a></p>