title: Alter column datatype in sql
body: <p>I am trying to rename the column datatype from text to ntext but getting error</p>
  
  <pre><code>Msg 4927, Level 16, State 1, Line 1
  Cannot alter column 'ColumnName' to be data type ntext.
  </code></pre>
  
  <p>query that i m using is as follows:-</p>
  
  <pre><code>alter table tablename alter column columnname ntext null
  </code></pre>