fix : fix error caused by empty vgroups when no user tables

source/libs/parser/src/parTranslater.c

@@ -1817,7 +1817,17 @@ static int32_t setVnodeSysTableVgroupList(STranslateContext* pCxt, SName* pName,
     code = getDBVgInfoImpl(pCxt, pName, &vgroupList);
   }
 
-  if (TSDB_CODE_SUCCESS == code && 0 == strcmp(pRealTable->table.tableName, TSDB_INS_TABLE_TABLES)) {
+  if (TSDB_CODE_SUCCESS == code &&
+      0 == strcmp(pRealTable->table.dbName, TSDB_INFORMATION_SCHEMA_DB) &&
+      0 == strcmp(pRealTable->table.tableName, TSDB_INS_TABLE_TAGS) &&
+      isSelectStmt(pCxt->pCurrStmt) &&
+      0 == taosArrayGetSize(vgroupList)) {
+    ((SSelectStmt*)pCxt->pCurrStmt)->isEmptyResult = true;
+  }
+
+  if (TSDB_CODE_SUCCESS == code &&
+      0 == strcmp(pRealTable->table.dbName, TSDB_INFORMATION_SCHEMA_DB) &&
+      0 == strcmp(pRealTable->table.tableName, TSDB_INS_TABLE_TABLES)) {
     code = addMnodeToVgroupList(&pCxt->pParseCxt->mgmtEpSet, &vgroupList);
   }