title: Get count if column value does not exist in another table
body: <p>I have the following two queries:</p>
  
  <pre><code>select count(*) from table_1 where c_id=12345
  
  select count(*) from table_2 where success=1 and c_id=12345
  </code></pre>
  
  <p>I add these two counts on the C# layer.  However, <code>table_1</code> and <code>table_2</code> both have a column called <code>m_id</code>.  I want to be able to get the total count where <code>table_2</code> has both these conditions:</p>
  
  <ul>
  <li><code>success=1 and c_id=12345</code> </li>
  <li>and <code>m_id</code> does not equal any <code>m_id</code> from <code>table_1 where c_id=12345</code>.  </li>
  </ul>
  
  <p>Is this possible to do?  Is it possible to do it in a single query? I'm still new to SQL, so I apologize if this an obvious question.</p>