diff --git a/session_convert.go b/session_convert.go
index 7f11354d..9009fadd 100644
--- a/session_convert.go
+++ b/session_convert.go
@@ -558,7 +558,10 @@ func (session *Session) value2Interface(col *core.Column, fieldValue reflect.Val
 		if col.SQLType.IsBlob() {
 			return data, nil
 		}
-		return string(data), nil
+		if len(data) > 0 {
+			return string(data), nil
+		}
+		return nil, nil
 	}
 
 	fieldType := fieldValue.Type()
diff --git a/statement.go b/statement.go
index ea3ecabe..454accb7 100644
--- a/statement.go
+++ b/statement.go
@@ -330,6 +330,11 @@ func (statement *Statement) buildUpdates(bean interface{},
 			if err != nil {
 				engine.logger.Error(err)
 			} else {
+				if fieldType.Kind() == reflect.Ptr && len(data) == 0 {
+					args = append(args, nil)
+					colNames = append(colNames, fmt.Sprintf("%v=?", engine.Quote(col.Name)))
+					continue
+				}
 				val = data
 			}
 			goto APPEND