diff --git a/app/Support/FilterBuilder/Entity/FilterItem.php b/app/Support/FilterBuilder/Entity/FilterItem.php
index 93f6969..4e34d7e 100644
--- a/app/Support/FilterBuilder/Entity/FilterItem.php
+++ b/app/Support/FilterBuilder/Entity/FilterItem.php
@@ -34,7 +34,7 @@ class FilterItem extends EntityJson
     /**
      * @var string
      */
-    protected string $interval;
+    protected string $interval = '';
 
     /**
      * @return bool
diff --git a/app/Support/FilterBuilder/FilterType.php b/app/Support/FilterBuilder/FilterType.php
index 8198530..0f7069b 100644
--- a/app/Support/FilterBuilder/FilterType.php
+++ b/app/Support/FilterBuilder/FilterType.php
@@ -63,7 +63,7 @@ class FilterType
             $fType = 'not like';
         }
 
-        if ($filter->getInterval())
+        if (!empty($filter->getInterval()))
         {
             $filter->setField("TO_DATE({$filter->getField()}, 'YYMM')");
             $filter->setValue(DB::raw("TO_DATE(TO_CHAR(current_date , 'YYYY-01-01'), 'YYYY-MM-DD') - INTERVAL