title: Delete statement in SQL
body: <p>I have these tables:</p>
  
  <ul>
  <li><code>Account</code> (<code>account-number (PK), branch-name (FK), balance</code>)</li>
  <li><code>Branch</code> (<code>branch-name (PK), branch-city, assets</code>)</li>
  </ul>
  
  <p>Could someone explain me what is the difference between the following two statements? I executed both of them at my database and the result of deleted rows was the same. Am I missing something? </p>
  
  <pre><code>delete from account
  where [branch-name] = 'London'
  </code></pre>
  
  <p>and </p>
  
  <pre><code>delete from account
  where [branch-name] in (select [branch-name]
                          from branch
                          where [branch-name]='London')
  </code></pre>