title: errors on php and mysql after moving to php 7
body: <p>I moved to a new server and now my script throws these errors:</p>
  <blockquote>
  <p>PHP Warning:  mysqli_query() expects at least 2 parameters, 1 given in /admin/classes/db_functionsClass.php on line 57</p>
  <p>PHP Fatal error:  Uncaught Error: Call to undefined function mysql_error() in /admin/classes/db_functionsClass.php:57 Stack trace:\n#0 /admin/index.php(45): db_functionsClass-&gt;selectQuery('tbl_adminuser', 'where username=...')</p>
  </blockquote>
  <p>This is line 57:</p>
  <pre><code>$this-&gt;result=mysqli_query($this-&gt;query) or die(mysql_error());
  </code></pre>
  <p>And line 45 from index file</p>
  <pre><code>$db-&gt;selectQuery($table,$condition);  // Executing Select Query.
  </code></pre>
  <p>And the whole function from db_function:</p>
  <pre><code>    function selectQuery($table,$condition,$fields=&quot;&quot;)
      {
          if(trim($fields)==&quot;&quot;)
                  $fields=&quot;*&quot;;
          $this-&gt;query=&quot;select $fields from $table $condition&quot;;
          $this-&gt;result=mysqli_query($this-&gt;query) or die(mysql_error());
          if($this-&gt;result)
          $this-&gt;num=mysql_num_rows($this-&gt;result);    
      }
  </code></pre>