fix: fix coredump if mode function with interval

src/client/src/tscUtil.c

@@ -1528,6 +1528,11 @@ void handleDownstreamOperator(SSqlObj** pSqlObjList, int32_t numOfUpstream, SQue
 
     tscDebug("0x%"PRIx64" create QInfo 0x%"PRIx64" to execute the main query while all nest queries are ready", pSql->self, pSql->self);
     px->pQInfo = createQInfoFromQueryNode(px, &tableGroupInfo, pSourceOperator, NULL, NULL, MASTER_SCAN, pSql->self);
+    if (px->pQInfo == NULL) {
+      tscAsyncResultOnError(pSql);
+      pOutput->code = TSDB_CODE_QRY_OUT_OF_MEMORY;
+      return;
+    }
 
     px->pQInfo->runtimeEnv.udfIsCopy = true;
     px->pQInfo->runtimeEnv.pUdfInfo = pUdfInfo;