Updated WHERE clause to ignore expressions when the argument value is not set.

git-svn-id: http://xe-core.googlecode.com/svn/branches/1.5.0-DB@8386 201d5d3c-b55e-5fd7-737f-ddc643e51545

classes/xml/xmlquery/argument/Argument.class.php

@@ -31,6 +31,8 @@
 		}
 		
 		function escapeValue($column_type){
+			if(!isset($this->value)) return;
+			if($column_type === '') $column_type = 'varchar';
 			if(in_array($column_type, array('date', 'varchar', 'char')))
 				$this->value = '\''.$this->value.'\'';
 		}