Merge pull request #5236 from taosdata/hotfix/TD-2978

[TD-2978]stop query when first round with empty result

src/client/src/tscSubquery.c

@@ -1981,7 +1981,8 @@ void tscFirstRoundRetrieveCallback(void* param, TAOS_RES* tres, int numOfRows) {
   // set the parameters for the second round query process
   SSqlCmd    *pPCmd   = &pParent->cmd;
   SQueryInfo *pQueryInfo1 = tscGetQueryInfoDetail(pPCmd, 0);
-
+  int32_t resRows = pSup->numOfRows;
+  
   if (pSup->numOfRows > 0) {
     SBufferWriter bw = tbufInitWriter(NULL, false);
     interResToBinary(&bw, pSup->pResult, pSup->tagLen);
@@ -1999,6 +2000,12 @@ void tscFirstRoundRetrieveCallback(void* param, TAOS_RES* tres, int numOfRows) {
 
   taos_free_result(pSql);
 
+  if (resRows == 0) {
+    pParent->cmd.command = TSDB_SQL_RETRIEVE_EMPTY_RESULT;
+    (*pParent->fp)(pParent->param, pParent, 0);
+    return;
+  }
+
   pQueryInfo1->round = 1;
   tscDoQuery(pParent);
 }