title: Adding a comment in alter command in oracle
body: <p>I am adding a column in oracle and I also want to add comments to describe the column. 
  Here's my syntax: </p>
  
  <pre><code>ALTER TABLE TableName ADD (ColumnName  VARCHAR(10) null COMMENT ON tableName.columnName IS 'some comments');
  </code></pre>
  
  <p>Her's the error: </p>
  
  <pre><code>SQL Error: ORA-00907: missing right parenthesis
  00907. 00000 -  "missing right parenthesis"
  *Cause:    
  *Action:
  </code></pre>
  
  <p>I will appreciate any help. </p>