修復錯誤

app/models/table_entry.rb

@@ -50,7 +50,7 @@ class TableEntry
 			if column_entries.nil?
 				values = self.order_by({field => direction})
 			else
-				values = column_entries.map{|v| v.table_entry}
+				values = column_entries.map{|v| v.table_entry}.compact
 				values = values.sort_by{|v| v.send(field)}
 				if direction == 'desc'
 					values = values.reverse