diff --git a/.gitignore b/.gitignore
index 66fd13c..55cc753 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,7 +4,7 @@
 *.dll
 *.so
 *.dylib
-
+tmp
 # Test binary, built with `go test -c`
 *.test
 
diff --git a/service/dao/dao.go b/service/dao/dao.go
index cd8a7f3..396c97e 100644
--- a/service/dao/dao.go
+++ b/service/dao/dao.go
@@ -64,6 +64,8 @@ func getBasicValue(valWarp *nebula.ValueWrapper) (common.Any, error) {
 		return valWarp.AsTime()
 	} else if valType == "datetime" {
 		return valWarp.AsDateTime()
+	} else if valType == "empty" {
+		return "_EMPTY_", nil
 	}
 	return "", nil
 }