gistfile1

Index: sapphire/core/model/Aggregate.php
===================================================================
--- sapphire/core/model/Aggregate.php	(revision 97402)
+++ sapphire/core/model/Aggregate.php	(working copy)
@@ -85,12 +85,18 @@
 		$attribute = $args ? $args[0] : 'ID';
 		
 		$table = null;
-		
-		foreach (ClassInfo::ancestry($this->type, true) as $class) {
+
+		$ancestry = ClassInfo::ancestry($this->type, true);
+		foreach ($ancestry as $class) {
 			$fields = DataObject::custom_database_fields($class);
 			if (array_key_exists($attribute, $fields)) { $table = $class; break; }
 		}
 		
+		// Special case for these built-in fields
+		if(!$table && in_array($attribute, array('LastEdited', 'Created', 'ClassName'))) {
+			$table = array_pop($ancestry);
+		}
+		
 		if (!$table) user_error("Couldn't find table for field $attribute in type {$this->type}", E_USER_ERROR);
 		
 		$query = $this->query("$func(\"$table\".\"$attribute\")");