diff --git a/filter.go b/filter.go
index 7274184..354f819 100644
--- a/filter.go
+++ b/filter.go
@@ -227,7 +227,7 @@ func (f *filter) getValue(dataType string, sourceValue gjson.Result, defaultValu
 		err = util.ConvertAssign(&val, sourceValueStr)
 		return val, err
 	case DataTypeString:
-		return defaultValue, nil
+		return sourceValueStr, nil
 	case DataTypeAny:
 		return sourceValue.Value(), nil
 	default: