title: Check for the existence of multiple columns
body: <p>I need to create a sql change script that checks for the existence of two columns in a table. If these columns do exist, the script will run alter table to add them. An example of how we check for 1 column is below.</p>
  
  <pre><code>IF NOT EXISTS(SELECT * FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = 'Table' AND COLUMN_NAME = 'ColumnC') 
  </code></pre>
  
  <p>So I need this script to check for the existence of ColumnC and ColumnD.</p>