title: what the meaning mergeBindings in laravel
body: <p>hy I'm new in laravel 4 and I have found code like this<br></p>
  
  <pre><code>$sub = Abc::where(..)-&gt;groupBy(..); // Eloquent Builder instance
  
  $count = DB::table( DB::raw("({$sub-&gt;toSql()}) as sub") )
  -&gt;mergeBindings($sub-&gt;getQuery()) 
  -&gt;count();
  </code></pre>
  
  <p>my quetion is<br>
  1. what the meaning <strong>mergeBindings($sub->getQuery())</strong> and give me example for using <strong>mergeBindings</strong></p>