title: How to check if a column exists before adding it to an existing table in PL/SQL?
body: <p>How do I add a simple check before adding a column to a table for an oracle db? I've included the SQL that I'm using to add the column.</p>
  
  <pre><code>ALTER TABLE db.tablename 
    ADD columnname NVARCHAR2(30);
  </code></pre>