--- a/admin/linkAmendments.php
+++ b/admin/linkAmendments.php
@@ -2,7 +2,7 @@
 include_once ("../lib/common.inc.php");
 $query = 'SELECT c."CNID",c."parentCN",p."childCN" FROM contractnotice as c  LEFT OUTER JOIN contractnotice as p on c."parentCN" = p."CNID"
 WHERE
-c."parentCN" > 0 AND p."childCN" IS NULL ';
+c."parentCN" IS NOT NULL AND p."childCN" IS NULL ';
 $query = $conn->prepare($query);
 	$query->execute();
 		databaseError($conn->errorInfo());
@@ -28,9 +28,9 @@
       FROM contractnotice
       GROUP BY "parentCN" 
       HAVING COUNT(*) > 1 
-      AND "parentCN" != 0
+      AND "parentCN" IS NOT NULL
 )
-AND "childCN" = 0
+AND "childCN" IS NULL
 GROUP BY "parentCN" having count(*) > 1';
 $query = $conn->prepare($query);
 	$query->execute();