diff --git a/Repositories/statistics/includes/inc.class.mysql.es.php b/Repositories/statistics/includes/inc.class.mysql.es.php
index 7c5d423..0ecd656 100755
--- a/Repositories/statistics/includes/inc.class.mysql.es.php
+++ b/Repositories/statistics/includes/inc.class.mysql.es.php
@@ -669,7 +669,7 @@
 	function addFourWeeksCondition ( $range, &$where_parts )
 	{
 		if ( $range == '4w' )
-			$this->addStringCondition( 'request_date', '>=', 'DATE_SUB(CURDATE(),INTERVAL 1 MONTH)', $where_parts );
+			$this->addExprCondition( 'request_date', '>=', 'DATE_SUB(CURDATE(),INTERVAL 1 MONTH)', $where_parts );
 	}
 
 	/*
@@ -714,6 +714,28 @@
 		$where_parts[] = "$column $op $value";
 	}
 
+	/*
+		NJS 2006-06-16
+		
+		addExprCondition()
+		arguments:
+			$column			the name of the SQL column
+			$op				the comparison operator
+			$expr			the expression to be tested
+			$where_parts	reference to an array to which to add the new
+							condition string
+		returns: void
+		
+		Add to the list of WHERE conditions a generic condition for a
+		column to be tested against some arbitrary expression. Any
+		validation of the value should be done prior to calling this
+		function.
+	*/
+	function addExprCondition ( $column, $op, $expr, &$where_parts )
+	{
+		$where_parts[] = "$column $op $expr";
+	}
+
 
 }