diff --git a/src/PHPCR/Util/QOM/Sql2Scanner.php b/src/PHPCR/Util/QOM/Sql2Scanner.php
index 74aa1b9..9afafe8 100644
--- a/src/PHPCR/Util/QOM/Sql2Scanner.php
+++ b/src/PHPCR/Util/QOM/Sql2Scanner.php
@@ -75,7 +75,8 @@ public function lookupNextToken($offset = 0)
      */
     public function getPreviousDelimiter()
     {
-        return $this->delimiters[$this->curpos - 1];
+
+        return isset($this->delimiters[$this->curpos - 1]) ? $this->delimiters[$this->curpos - 1] : ' ';
     }
 
     /**