diff --git a/inc/caldav-REPORT-cardquery.php b/inc/caldav-REPORT-cardquery.php
index bbfc2f73..ef97160e 100644
--- a/inc/caldav-REPORT-cardquery.php
+++ b/inc/caldav-REPORT-cardquery.php
@@ -131,6 +131,7 @@ function SqlFilterCardDAV( $filter, $components, $property = null, $parameter =
       }
 
       $collation = $filter->GetAttribute("collation");
+      if (! isset($collation) ) $collation = '';
       switch( strtolower($collation) ) {
         case 'i;octet':
           $comparison = 'LIKE';
@@ -144,6 +145,7 @@ function SqlFilterCardDAV( $filter, $components, $property = null, $parameter =
 
       $search = $filter->GetContent();
       $match  = $filter->GetAttribute("match-type");
+      if (! isset($match) ) $match = '';
       switch( strtolower($match) ) {
         case 'equals':
           break;