title: MySQL PDO: Using bound placeholder within a regular expression
body: <p>Here's a PHP snippet attempting to fetch some rows from a MySQL table:</p>
  
  <pre><code>$connect = dbconn(PROJHOST,'dbcontext', PROJDBUSER, PROJDBPWD);
  $sql= "SELECT contextleft, contextright 
         FROM tblcontext 
         WHERE contextleft REGEXP '[[:&lt;:]]:word[[:&gt;:]]' 
         LIMIT 0, 10";
  $xleft = array();
  $xright = array();
  $countrows = 0;
  $query = $connect-&gt;prepare($sql);
  $query-&gt;bindParam(':word', $term);
  if($query-&gt;execute()) {
      $rows = $query-&gt;fetchAll(PDO::FETCH_ASSOC);
      foreach($rows as $row){
          $xleft[$countrows] = $row['contextleft'];
          $xright[$countrows] = $row['contextright'];
          $countrows++;
      }
      $notfound = null;
  }
  </code></pre>
  
  <p>I reckon there's some problem with the following line in the above code:</p>
  
  <pre><code>$sql= "SELECT contextleft, contextright FROM tblcontext WHERE contextleft REGEXP '[[:&lt;:]]:word[[:&gt;:]]' LIMIT 0, 10";
  </code></pre>
  
  <p>Basically, I need to run a regex that matches a word (bound by the <em>:word</em> placeholder) and returns matching records. The code is otherwise fine because it works without the regex. But somehow it refuses to return anything when I use the regex. Is there something wrong with the way I have used the placeholder parameter within the regex?</p>
  
  <p>In a nutshell, my question is how can one use a bound placeholder inside of a regular expression?</p>
  
  <p><strong>ADDITIONAL INFO</strong>: The table is named <strong>tblcontext</strong> with the following structure:</p>
  
  <pre><code>Engine MyISAM
  sn: int(11), auto-increment, primary key
  contextleft: varchar(190), fulltext index, unique
  contextright: varchar(190), fulltext index, unique
  </code></pre>
  
  <p>Some random examples that should match when the user enters, say, <em>fly</em>:</p>
  
  <pre><code>I want to fly
  To fly is easy
  She will never fly because she is too heavy
  </code></pre>
  
  <p>Some random examples that should NOT match when the user enters <em>fly</em>:</p>
  
  <pre><code>Flying is easy
  There is a blowfly on your food
  She has been flying since last night
  </code></pre>
  
  <p>I cannot use FULLTEXT search for examples like the above because it only works for search strings larger than 3 characters.</p>