title: ERROR 1062 (23000): Duplicate entry for key 'PRIMARY'
body: <p>I am trying to add a new column to sql table -</p>
  
  <pre><code>ALTER TABLE table1 ADD COLUMN column1 VARCHAR(400) DEFAULT NULL;
  </code></pre>
  
  <p>But i am getting this error -</p>
  
  <blockquote>
    <p>ERROR 1062 (23000): Duplicate entry '82133627' for key 'PRIMARY'</p>
  </blockquote>
  
  <p>In table1, we just have one primary key, and i ran the following command to see what's the result -</p>
  
  <pre><code>select * from table1 where &lt;primary_key_field&gt;='82133627';
  </code></pre>
  
  <p>Got 1 row in set</p>
  
  <pre><code>Primary key - primary_key_field int(11) NOT NULL
  </code></pre>
  
  <p>Also, i went thru some of the responses for similar errors where they suggested to check if the primary key has auto-increment. We just have one primary key in this table, and it does not have auto-increment.</p>
  
  <p>How can I solve this? </p>