"ERROR: for SELECT DISTINCT, ORDER BY expressions must appear in select list" when on PostgreSQL

Hello,
when I have installed module on PostgreSQL, I was unable to see pages like /nodeorder/term/15. This was because of error produced by taxonomy_select_nodes:

pg_query() [function.pg-query]: Query failed: ERROR: for SELECT DISTINCT, ORDER BY expressions must appear in select list in /usr/share/drupal/includes/database.pgsql.inc on line 126.

I had to do these changes in nodeorder.module:

--- nodeorder.orig/nodeorder.module	2007-06-16 00:47:16.000000000 +0200
+++ nodeorder/nodeorder.module	2012-06-09 22:29:10.000000000 +0200
@@ -162,10 +162,10 @@
       //
       // First sort by sticky, then by weight_in_tid...
       if ($operator == 'or') {
-        $order = 'n.sticky DESC, tn.weight_in_tid';
+        $order = 'n.sticky DESC, tn.weight_in_tid DESC';
       }
       else {
-        $order = 'n.sticky DESC, tn0.weight_in_tid';
+        $order = 'n.sticky DESC, tn0.weight_in_tid DESC';
       }
       
       switch ($op) {
@@ -186,7 +186,7 @@
             }
           }
 
-          $output .= taxonomy_render_nodes(taxonomy_select_nodes($tids, $operator, $depth, TRUE, $order));
+          $output .= taxonomy_render_nodes(nodeorder_select_nodes($tids, $operator, $depth, TRUE, $order));
           $output .= theme('feed_icon', url('taxonomy/term/'. $str_tids .'/'. $depth .'/feed'));
           return $output;
           break;
@@ -253,17 +253,19 @@
 
     if ($operator == 'or') {
       $str_tids = implode(',', call_user_func_array('array_merge', $descendant_tids));
-      $sql = 'SELECT DISTINCT(n.nid), n.sticky, n.title, n.created FROM {node} n INNER JOIN {term_node} tn ON n.nid = tn.nid WHERE tn.tid IN ('. $str_tids .') AND n.status = 1 ORDER BY '. $order;
+      $sql = 'SELECT DISTINCT(n.nid), n.sticky, n.title, n.created, tn.weight_in_tid FROM {node} n INNER JOIN {term_node} tn ON n.nid = tn.nid WHERE tn.tid IN ('. $str_tids .') AND n.status = 1 ORDER BY '. $order;
       $sql_count = 'SELECT COUNT(DISTINCT(n.nid)) FROM {node} n INNER JOIN {term_node} tn ON n.nid = tn.nid WHERE tn.tid IN ('. $str_tids .') AND n.status = 1';
     }
     else {
       $joins = '';
       $wheres = '';
+      $selects = '';
       foreach ($descendant_tids as $index => $tids) {
         $joins .= ' INNER JOIN {term_node} tn'. $index .' ON n.nid = tn'. $index .'.nid';
         $wheres .= ' AND tn'. $index .'.tid IN ('. implode(',', $tids) .')';
+        $selects .= ' , tn'. $index .'.weight_in_tid';
       }
-      $sql = 'SELECT DISTINCT(n.nid), n.sticky, n.title, n.created FROM {node} n '. $joins .' WHERE n.status = 1 '. $wheres .' ORDER BY '. $order;
+      $sql = 'SELECT DISTINCT(n.nid), n.sticky, n.title, n.created '. $selects .' FROM {node} n '. $joins .' WHERE n.status = 1 '. $wheres .' ORDER BY '. $order;
       $sql_count = 'SELECT COUNT(DISTINCT(n.nid)) FROM {node} n '. $joins .' WHERE n.status = 1 '. $wheres;
     }
     $sql = db_rewrite_sql($sql);
@@ -502,7 +504,6 @@
   // Note that it would be nice to wrap this in a transaction...
   
   // We rely on the fact that every node has a unique weight_in_tid
-  // (initially equal to negative one times its nid)...
   $weight = db_result(db_query("SELECT weight_in_tid FROM {term_node} WHERE nid = %d AND tid = %d", $node->nid, $tid));
 
   if ($up) {

Mostly it is about enhancing local copy of nodeorder_select_nodes to include tn.weight_in_tid in the select list. I have also removed comment which says weight_in_tid have negative numbers.

I'm not sure about all this here, but now it works for me.