title: ALTER COLUMN IF EXISTS
body: <p>I would like to alter the table if the table has the column with same data type and number exists</p>
  
  <p>Original tTable structure is </p>
  
  <p>TableName</p>
  
  <pre><code>ColumnName NVARCHAR(100)
  </code></pre>
  
  <p>Code for altering column if <code>ColumnName</code> with <code>NVARCHAR</code> and length 100 exists</p>
  
  <pre><code>IF EXISTS(...)
  BEGIN
      ALTER TABLE [dbo].[TableName]
      ALTER COLUMN [ColumnName] NVARCHAR(200) [NULL|NOT NULL]
  END
  </code></pre>
  
  <p>What find query I need to insert at <code>IF EXISTS(...)</code>?</p>