diff --git a/process/Contact_lib/process.js b/process/Contact_lib/process.js
index 09c53387243396a1d82be38c42de96ba4fadbff3..fc7f681f31f66f73b2ea8e054bd7dc388f5e3a78 100644
--- a/process/Contact_lib/process.js
+++ b/process/Contact_lib/process.js
@@ -744,7 +744,7 @@ ContactUtils.getCommFilter = function(pOperator, pRawvalue, pFilterOperatorName,
             resultSqlCond = resultSqlCond + " '%" + pRawvalue + "')";
             break;
         case "ISNULL":
-            resultSqlCond = "CONTACTID not in (" + commpart + ")";
+            resultSqlCond = newWhere("CONTACT.CONTACTID", commpart, SqlBuilder.NOT_IN()).toString();
             break;
         case "ISNOTNULL":
             resultSqlCond = resultSqlCond + ")";