--- a/admin/linkAmendments.php
+++ b/admin/linkAmendments.php
@@ -1,5 +1,11 @@
 <?php
 include_once ("../lib/common.inc.php");
+$query = 'update contractnotice set "parentCN" = null where "parentCN" = \'0\'';
+$query = $conn->prepare($query);
+	$query->execute();
+        $query = 'update contractnotice set "supplierABN" = null where "supplierABN" = \'0\'';
+$query = $conn->prepare($query);
+	$query->execute();
 $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" IS NOT NULL AND p."childCN" IS NULL ';
@@ -7,6 +13,7 @@
 	$query->execute();
 		databaseError($conn->errorInfo());
 foreach ($query->fetchAll() as $row) {
+    if ($row['parentCN'] != 0) {
   $conn->exec('UPDATE contractnotice SET "childCN" = \'' .
 			 $row['CNID'] . '\' where "CNID" = \'' .
 			 $row['parentCN'] . '\';');
@@ -19,7 +26,7 @@
                   echo $row['CNID'] . " linked to parent " . $row['parentCN'] .
   "<br>\n";
   else print_r($errors);
-
+    }
 }
 // also need to eliminate CN 100528/100529 - check for double parent CNs with no childCN, latest sequent CN id keeps childCN = 0
 $query = 'SELECT "parentCN", array_agg("CNID"), count(*) from contractnotice WHERE "parentCN" IN