--- a/displayBubbletree.php
+++ b/displayBubbletree.php
@@ -51,7 +51,7 @@
 
 $catthreesresult = $conn->prepare('SELECT substr( "categoryUNSPSC"::text, 0, 4 ) as cat , SUM( "value" ) as value
 FROM contractnotice
-WHERE "childCN" = 0 and "categoryUNSPSC" IS NOT NULL
+WHERE "childCN" is null and "categoryUNSPSC" IS NOT NULL
 GROUP BY cat order by cat ;');
 $catthreesresult->execute();
 		foreach ($catthreesresult->fetchAll() as $threerow) {