Index: modules/forum/forum.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/forum/forum.module,v
retrieving revision 1.448.2.7
diff -p -u -p -r1.448.2.7 forum.module
--- modules/forum/forum.module	3 Jun 2009 18:27:48 -0000	1.448.2.7
+++ modules/forum/forum.module	27 Oct 2009 21:24:43 -0000
@@ -495,11 +495,31 @@ function forum_get_forums($tid = 0) {
   $_forums = taxonomy_get_tree($vid, $tid);
 
   if (count($_forums)) {
-
-    $counts = array();
-
-    $sql = "SELECT r.tid, COUNT(n.nid) AS topic_count, SUM(l.comment_count) AS comment_count FROM {node} n INNER JOIN {node_comment_statistics} l ON n.nid = l.nid INNER JOIN {term_node} r ON n.vid = r.vid WHERE n.status = 1 GROUP BY r.tid";
-    $sql = db_rewrite_sql($sql);
+  $counts = array();
+    $sql = "
+      SELECT r.tid AS tid, n.nid AS nid, l.comment_count AS nid_comment_count
+        FROM {node} n
+        INNER JOIN {node_comment_statistics} l ON n.nid = l.nid
+        INNER JOIN {term_node} r ON n.vid = r.vid
+        WHERE n.status = 1
+        GROUP BY r.tid, n.nid, l.comment_count";
+    $sql_rewritten = db_rewrite_sql($sql);
+    if ($sql_rewritten == $sql) {
+      $sql = "
+        SELECT r.tid, COUNT(n.nid) AS topic_count, SUM(l.comment_count) AS comment_count
+          FROM {node} n
+          INNER JOIN {node_comment_statistics} l ON n.nid = l.nid
+          INNER JOIN {term_node} r ON n.vid = r.vid
+          WHERE n.status = 1
+          GROUP BY r.tid";
+      $sql = db_rewrite_sql($sql);
+    }
+    else {
+      $sql = "
+        SELECT tid, COUNT(nid) AS topic_count, SUM(nid_comment_count) AS comment_count
+          FROM ($sql_rewritten) AS forum_content_list
+          GROUP BY tid";
+    }
     $_counts = db_query($sql);
     while ($count = db_fetch_object($_counts)) {
       $counts[$count->tid] = $count;