diff --git a/lib/CalDAV/Backend/PDO.php b/lib/CalDAV/Backend/PDO.php
index bb12d590da..acda1c9cbd 100644
--- a/lib/CalDAV/Backend/PDO.php
+++ b/lib/CalDAV/Backend/PDO.php
@@ -789,8 +789,10 @@ public function calendarQuery($calendarId, array $filters)
 
                 // If start time OR the end time is not specified, we can do a
                 // 100% accurate mysql query.
-                if (!$filters['prop-filters'] && !$filters['comp-filters'][0]['comp-filters'] && !$filters['comp-filters'][0]['prop-filters'] && (!$timeRange['start'] || !$timeRange['end'])) {
-                    $requirePostFilter = false;
+                if (!$filters['prop-filters'] && !$filters['comp-filters'][0]['comp-filters'] && !$filters['comp-filters'][0]['prop-filters'] && $timeRange) {
+                    if ((array_key_exists('start', $timeRange) && !$timeRange['start']) || (array_key_exists('end', $timeRange) && !$timeRange['end'])) {
+                        $requirePostFilter = false;
+                    }
                 }
             }
         }
@@ -810,11 +812,11 @@ public function calendarQuery($calendarId, array $filters)
             $values['componenttype'] = $componentType;
         }
 
-        if ($timeRange && $timeRange['start']) {
+        if ($timeRange && array_key_exists('start', $timeRange) && $timeRange['start']) {
             $query .= ' AND lastoccurence > :startdate';
             $values['startdate'] = $timeRange['start']->getTimeStamp();
         }
-        if ($timeRange && $timeRange['end']) {
+        if ($timeRange && array_key_exists('end', $timeRange) && $timeRange['end']) {
             $query .= ' AND firstoccurence < :enddate';
             $values['enddate'] = $timeRange['end']->getTimeStamp();
         }
diff --git a/lib/CalDAV/CalendarQueryValidator.php b/lib/CalDAV/CalendarQueryValidator.php
index ab6c602d2e..8217da0b69 100644
--- a/lib/CalDAV/CalendarQueryValidator.php
+++ b/lib/CalDAV/CalendarQueryValidator.php
@@ -69,7 +69,15 @@ protected function validateCompFilters(VObject\Component $parent, array $filters
 
             if ($filter['time-range']) {
                 foreach ($parent->{$filter['name']} as $subComponent) {
-                    if ($this->validateTimeRange($subComponent, $filter['time-range']['start'], $filter['time-range']['end'])) {
+                    $start = null;
+                    $end = null;
+                    if (array_key_exists('start', $filter['time-range'])) {
+                        $start = $filter['time-range']['start'];
+                    }
+                    if (array_key_exists('end', $filter['time-range'])) {
+                        $end = $filter['time-range']['end'];
+                    }
+                    if ($this->validateTimeRange($subComponent, $start, $end)) {
                         continue 2;
                     }
                 }
@@ -130,7 +138,15 @@ protected function validatePropFilters(VObject\Component $parent, array $filters
 
             if ($filter['time-range']) {
                 foreach ($parent->{$filter['name']} as $subComponent) {
-                    if ($this->validateTimeRange($subComponent, $filter['time-range']['start'], $filter['time-range']['end'])) {
+                    $start = null;
+                    $end = null;
+                    if (array_key_exists('start', $filter['time-range'])) {
+                        $start = $filter['time-range']['start'];
+                    }
+                    if (array_key_exists('end', $filter['time-range'])) {
+                        $end = $filter['time-range']['end'];
+                    }
+                    if ($this->validateTimeRange($subComponent, $start, $end)) {
                         continue 2;
                     }
                 }
diff --git a/tests/Sabre/CalDAV/Backend/AbstractPDOTest.php b/tests/Sabre/CalDAV/Backend/AbstractPDOTest.php
index 9460b89228..77817c4fd0 100644
--- a/tests/Sabre/CalDAV/Backend/AbstractPDOTest.php
+++ b/tests/Sabre/CalDAV/Backend/AbstractPDOTest.php
@@ -780,7 +780,7 @@ public function testCalendarQueryTimeRange()
         ], $backend->calendarQuery([1, 1], $filters));
     }
 
-    public function testCalendarQueryTimeRangeNoEnd()
+    public function testCalendarQueryTimeRangeEndNull()
     {
         $backend = new PDO($this->pdo);
         $backend->createCalendarObject([1, 1], 'todo', "BEGIN:VCALENDAR\r\nBEGIN:VTODO\r\nEND:VTODO\r\nEND:VCALENDAR\r\n");
@@ -811,6 +811,94 @@ public function testCalendarQueryTimeRangeNoEnd()
         ], $backend->calendarQuery([1, 1], $filters));
     }
 
+    public function testCalendarQueryTimeRangeNoEnd()
+    {
+        $backend = new PDO($this->pdo);
+        $backend->createCalendarObject([1, 1], 'todo', "BEGIN:VCALENDAR\r\nBEGIN:VTODO\r\nEND:VTODO\r\nEND:VCALENDAR\r\n");
+        $backend->createCalendarObject([1, 1], 'event', "BEGIN:VCALENDAR\r\nBEGIN:VEVENT\r\nDTSTART:20120101\r\nEND:VEVENT\r\nEND:VCALENDAR\r\n");
+        $backend->createCalendarObject([1, 1], 'event2', "BEGIN:VCALENDAR\r\nBEGIN:VEVENT\r\nDTSTART:20120103\r\nEND:VEVENT\r\nEND:VCALENDAR\r\n");
+
+        $filters = [
+            'name' => 'VCALENDAR',
+            'comp-filters' => [
+                [
+                    'name' => 'VEVENT',
+                    'comp-filters' => [],
+                    'prop-filters' => [],
+                    'is-not-defined' => false,
+                    'time-range' => [
+                        'start' => new \DateTime('20120102'),
+                    ],
+                ],
+            ],
+            'prop-filters' => [],
+            'is-not-defined' => false,
+            'time-range' => null,
+        ];
+
+        $this->assertEquals([
+            'event2',
+        ], $backend->calendarQuery([1, 1], $filters));
+    }
+
+    public function testCalendarQueryTimeRangeNoStart()
+    {
+        $backend = new PDO($this->pdo);
+        $backend->createCalendarObject([1, 1], 'todo', "BEGIN:VCALENDAR\r\nBEGIN:VTODO\r\nEND:VTODO\r\nEND:VCALENDAR\r\n");
+        $backend->createCalendarObject([1, 1], 'event', "BEGIN:VCALENDAR\r\nBEGIN:VEVENT\r\nDTSTART:20120101\r\nEND:VEVENT\r\nEND:VCALENDAR\r\n");
+        $backend->createCalendarObject([1, 1], 'event2', "BEGIN:VCALENDAR\r\nBEGIN:VEVENT\r\nDTSTART:20120103\r\nEND:VEVENT\r\nEND:VCALENDAR\r\n");
+
+        $filters = [
+            'name' => 'VCALENDAR',
+            'comp-filters' => [
+                [
+                    'name' => 'VEVENT',
+                    'comp-filters' => [],
+                    'prop-filters' => [],
+                    'is-not-defined' => false,
+                    'time-range' => [
+                        'end' => new \DateTime('20120102'),
+                    ],
+                ],
+            ],
+            'prop-filters' => [],
+            'is-not-defined' => false,
+            'time-range' => null,
+        ];
+
+        $this->assertEquals([
+            'event',
+        ], $backend->calendarQuery([1, 1], $filters));
+    }
+
+    public function testCalendarQueryTimeRangeNotSpecified()
+    {
+        $backend = new PDO($this->pdo);
+        $backend->createCalendarObject([1, 1], 'todo', "BEGIN:VCALENDAR\r\nBEGIN:VTODO\r\nEND:VTODO\r\nEND:VCALENDAR\r\n");
+        $backend->createCalendarObject([1, 1], 'event', "BEGIN:VCALENDAR\r\nBEGIN:VEVENT\r\nDTSTART:20120101\r\nEND:VEVENT\r\nEND:VCALENDAR\r\n");
+        $backend->createCalendarObject([1, 1], 'event2', "BEGIN:VCALENDAR\r\nBEGIN:VEVENT\r\nDTSTART:20120103\r\nEND:VEVENT\r\nEND:VCALENDAR\r\n");
+
+        $filters = [
+            'name' => 'VCALENDAR',
+            'comp-filters' => [
+                [
+                    'name' => 'VEVENT',
+                    'comp-filters' => [],
+                    'prop-filters' => [],
+                    'is-not-defined' => false,
+                    'time-range' => false,
+                ],
+            ],
+            'prop-filters' => [],
+            'is-not-defined' => false,
+            'time-range' => null,
+        ];
+
+        $result = $backend->calendarQuery([1, 1], $filters);
+        $this->assertTrue(in_array('event', $result));
+        $this->assertTrue(in_array('event2', $result));
+    }
+
     public function testGetChanges()
     {
         $backend = new PDO($this->pdo);