title: How to get all not null columns in a table
body: <p>I have a requirement to find all not-null columns in a table. For example, my table is the below one</p>
  
  <p><a href="https://i.stack.imgur.com/krl0e.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/krl0e.jpg" alt="enter image description here"></a></p>
  
  <p>Lets say, Column1, Column2 and Column3 have not-null constraints and Column4, Column5 and Column6 are of nullable types. Is there any query in Oracle that list the column names that are of not-null types, ie I need to get the column names Column1, Column2 and Column3.</p>
  
  <p><strong>DESIRED OUTPUT</strong><BR></p>
  
  <pre><code>Column1
  Column2
  Column3
  </code></pre>
  
  <p>I know there should be a simple way to achieve this, but am new to Oracle. Any help would be highly appreciated.</p>