title: An error when I add a variable to a string
body: <p>I have this line of SQL:</p>
  
  <pre><code>$sql = "SELECT ID, ListStID, ListEmail, Title FROM $entry_database WHERE ID = '". $ReqBookID ."'";
  $result = mysqli_query($conn, $sql);
  </code></pre>
  
  <p>As you can see, I am selecting an entry's ID, ListStID, ListEmail and Title Column if ID is equal to a string of numbers (or text), which is given by user in a form.</p>
  
  <p>Everything is ok, and I don't get any syntax error when I write the code (I am using a code editor software. However, when I use it online, I get this error:</p>
  
  <blockquote>
    <p>Error: SELECT ID, ListStID, ListEmail, Title FROM WHERE ID = '4' You
    have an error in your SQL syntax; check the manual that corresponds to
    your MariaDB server version for the right syntax to use near 'WHERE ID
    = '4'' at line 1</p>
  </blockquote>
  
  <p>I am very new to PHP, and I'm sure I am either adding extra ' or ", so I would really appreciate it if you could help me with this issue. I have tried the answers for similar questions, but no success yet.</p>