From 9f8d33dbdb67d1e7dd8ce8c181bf1aa7dddd5a6e Mon Sep 17 00:00:00 2001
From: wenshao <szujobs@hotmail.com>
Date: Sun, 1 Jun 2014 10:45:10 +0800
Subject: [PATCH] bug fixed for visitor

---
 .../com/alibaba/druid/sql/visitor/SQLEvalVisitorUtils.java   | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/main/java/com/alibaba/druid/sql/visitor/SQLEvalVisitorUtils.java b/src/main/java/com/alibaba/druid/sql/visitor/SQLEvalVisitorUtils.java
index 10e5359333..892a8d800c 100644
--- a/src/main/java/com/alibaba/druid/sql/visitor/SQLEvalVisitorUtils.java
+++ b/src/main/java/com/alibaba/druid/sql/visitor/SQLEvalVisitorUtils.java
@@ -808,6 +808,11 @@ public class SQLEvalVisitorUtils {
             x.putAttribute(EVAL_VALUE, EVAL_ERROR);
             return false;
         }
+        
+        if (val == null) {
+            x.putAttribute(EVAL_VALUE, EVAL_VALUE_NULL);
+            return false;
+        }
 
         switch (x.getOperator()) {
             case BINARY: