diff --git a/DatabaseMysql.php b/DatabaseMysql.php
index a7ecbbf..87fb91f 100644
--- a/DatabaseMysql.php
+++ b/DatabaseMysql.php
@@ -4,7 +4,8 @@
  * Very stable interface for MySQL - object-oriented at last :)
  * Select builder is inspired by MediaWiki's one.
  * Also usable for querying SphinxQL.
- * (c) Vitaliy Filippov, 2012-2013
+ * Version: 2015-05-12
+ * (c) Vitaliy Filippov, 2012-2015
  */
 
 if (!defined('MS_HASH'))
@@ -18,7 +19,13 @@ if (!defined('MS_HASH'))
     define('MS_RESULT', 8);
 }
 
-class DatabaseException extends Exception {}
+class DatabaseException extends Exception
+{
+    function isDuplicateKey()
+    {
+        return $this->getCode() == 1062;
+    }
+}
 
 if (!interface_exists('Database'))
 {
@@ -30,7 +37,7 @@ class DatabaseMysql implements Database
     var $host, $port, $socket, $username, $password, $dbname;
 
     var $tableNames = array();
-    var $queryLogFile;
+    var $queryLogFile, $loggedQueries = '';
     var $reconnect = true;
     var $autoBegin;
     var $ondestroy = 'commit';
@@ -89,6 +96,10 @@ class DatabaseMysql implements Database
             $this->transactions = array(false);
             $this->$o();
         }
+        if ($this->queryLogFile)
+        {
+            file_put_contents($this->queryLogFile, $this->loggedQueries, FILE_APPEND);
+        }
     }
 
     function connect()
@@ -167,7 +178,7 @@ class DatabaseMysql implements Database
         $this->queryCount++;
         if ($this->queryLogFile)
         {
-            file_put_contents($this->queryLogFile, date("[Y-m-d H:i:s] ").$sql."\n", FILE_APPEND);
+            $this->loggedQueries .= date("[Y-m-d H:i:s] ").$sql."\n";
         }
         $r = $this->link->query($sql, $fetchMode);
         if (!$r)
@@ -356,11 +367,36 @@ class DatabaseMysql implements Database
                 else
                 {
                     if (is_array(reset($v)))
+                    {
+                        // (a,b) IN ((1,2), (3,4)) ...
                         foreach ($v as &$l)
+                        {
                             $l = "(" . implode(",", array_map(array($this, 'quote'), $l)) . ")";
+                        }
+                        $wh[] = "$k IN (" . implode(",", $v) . ")";
+                    }
                     else
-                        $v = array_map(array($this, 'quote'), $v);
-                    $wh[] = "$k IN (" . implode(",", $v) . ")";
+                    {
+                        $r = '';
+                        $null = false;
+                        foreach ($v as $i => $l)
+                        {
+                            if ($l === NULL)
+                            {
+                                $null = true;
+                            }
+                            else
+                            {
+                                $r .= $this->quote($l).',';
+                            }
+                        }
+                        $r = $r !== '' ? "$k IN (" . substr($r, 0, -1) . ")" : '';
+                        if ($null)
+                        {
+                            $r = $r !== '' ? "($r OR $k IS NULL)" : "$k IS NULL";
+                        }
+                        $wh[] = $r;
+                    }
                 }
             }
             elseif (preg_match('/^-?\d+(\.\d+)?$/s', $v)) // int/float
@@ -403,6 +439,7 @@ class DatabaseMysql implements Database
      *   Sphinx Search extensions:
      *   'WITHIN GROUP ORDER BY' => array($orderby_field => 'ASC')
      *   'FIELD_WEIGHTS' => array('field' => <weight>, ...)
+     *   'RANKER' => bm25|sph04|...|expr('...ranker expression...')
      */
     function select_builder($tables, $fields, $where, $options = NULL)
     {
@@ -449,15 +486,24 @@ class DatabaseMysql implements Database
             $sql .= " WITHIN GROUP ORDER BY ".$this->order_option($options['WITHIN GROUP ORDER BY']);
         }
         $sql .= $this->limit_option($options);
-        if (!empty($options['FIELD_WEIGHTS']))
+        if (!empty($options['FIELD_WEIGHTS']) || !empty($options['RANKER']))
         {
             // Sphinx Search extension
-            $weights = array();
-            foreach ($options['FIELD_WEIGHTS'] as $f => $w)
+            $opt = array();
+            if (!empty($options['FIELD_WEIGHTS']))
             {
-                $weights[] = "`$f`=$w";
+                $weights = array();
+                foreach ($options['FIELD_WEIGHTS'] as $f => $w)
+                {
+                    $weights[] = "`$f`=$w";
+                }
+                $opt[] = "field_weights=(".implode(', ', $weights).")";
             }
-            $sql .= " OPTION field_weights=(".implode(', ', $weights).")";
+            if (!empty($options['RANKER']))
+            {
+                $opt[] = "ranker=".$options['RANKER'];
+            }
+            $sql .= " OPTION ".implode(', ', $opt);
         }
         if (isset($options['FOR UPDATE']))
             $sql .= ' FOR UPDATE';