From 6eb3da841dfa77b2b53c145749cdba23ced2fa6c Mon Sep 17 00:00:00 2001
From: Tim Price <timprice@catalyst-au.net>
Date: Tue, 16 Dec 2014 11:45:10 +1100
Subject: [PATCH] MDL-48421 navigation: accounting for potential regression

---
 lib/navigationlib.php | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/lib/navigationlib.php b/lib/navigationlib.php
index 5adc4ff7ad9..6ba84f9869b 100644
--- a/lib/navigationlib.php
+++ b/lib/navigationlib.php
@@ -1632,13 +1632,15 @@ class global_navigation extends navigation_node {
             // have been loaded
             $addedcategories = $this->addedcategories;
             unset($addedcategories[$categoryid]);
-            list($sql, $params) = $DB->get_in_or_equal(array_keys($addedcategories), SQL_PARAMS_NAMED, 'parent', false);
-            if ($showbasecategories) {
-                // We need to include categories with parent = 0 as well
-                $sqlwhere .= " AND (cc.parent = :categoryid OR cc.parent = 0) AND cc.parent {$sql}";
-            } else {
-                // All we need is categories that match the parent
-                $sqlwhere .= " AND cc.parent = :categoryid AND cc.parent {$sql}";
+            if (count($addedcategories) > 0) {
+                list($sql, $params) = $DB->get_in_or_equal(array_keys($addedcategories), SQL_PARAMS_NAMED, 'parent', false);
+                if ($showbasecategories) {
+                    // We need to include categories with parent = 0 as well
+                    $sqlwhere .= " AND (cc.parent = :categoryid OR cc.parent = 0) AND cc.parent {$sql}";
+                } else {
+                    // All we need is categories that match the parent
+                    $sqlwhere .= " AND cc.parent = :categoryid AND cc.parent {$sql}";
+                }
             }
             $params['categoryid'] = $categoryid;
         } else {