Fixed bug: the first node's id is not calculated correctly

modules/node.module

@@ -149,6 +149,7 @@ function node_save($node, $filter) {
     $node->created = time();
     $node->changed = time();
     $node->nid = db_result(db_query("SELECT MAX(nid) + 1 FROM node"));
+    $node->nid = empty($node->nid) ? 1 : $node->nid; 
 
     // Prepare the query:
     foreach ($node as $key => $value) {

modules/node/node.module

@@ -149,6 +149,7 @@ function node_save($node, $filter) {
     $node->created = time();
     $node->changed = time();
     $node->nid = db_result(db_query("SELECT MAX(nid) + 1 FROM node"));
+    $node->nid = empty($node->nid) ? 1 : $node->nid; 
 
     // Prepare the query:
     foreach ($node as $key => $value) {