diff --git a/src/query/src/qAggMain.c b/src/query/src/qAggMain.c
index 69166700aa4b2c25dcb0f04c5a80b5fb331eb83c..b7862a96fc93fbe0fde68640df6b6ac313ca9493 100644
--- a/src/query/src/qAggMain.c
+++ b/src/query/src/qAggMain.c
@@ -5196,7 +5196,7 @@ static bool unique_function_setup(SQLFunctionCtx *pCtx, SResultRowCellInfo* pRes
 }
 
 static void do_unique_function(SQLFunctionCtx *pCtx, SUniqueFuncInfo *pInfo, TSKEY timestamp, char *pData, char *tag, int32_t bytes){
-  UniqueUnit *unique = taosHashGet(*pCtx->pUniqueSet, pData, bytes);
+  UniqueUnit **unique = taosHashGet(*pCtx->pUniqueSet, pData, bytes);
   if (unique == NULL) {
     size_t size = sizeof(UniqueUnit) + bytes + pCtx->tagInfo.tagsLen;
     char *tmp = pInfo->res + pInfo->num * size;
@@ -5224,8 +5224,8 @@ static void do_unique_function(SQLFunctionCtx *pCtx, SUniqueFuncInfo *pInfo, TSK
 
     taosHashPut(*pCtx->pUniqueSet, pData, bytes, &tmp, sizeof(UniqueUnit*));
     pInfo->num++;
-  }else if(unique->timestamp > timestamp){
-    unique->timestamp = timestamp;
+  }else if((*unique)->timestamp > timestamp){
+    (*unique)->timestamp = timestamp;
   }
 }