diff --git a/src/client/inc/tscUtil.h b/src/client/inc/tscUtil.h
index 1e151584a1674b3178fa53ea9caee3ee0d836f93..536fcc7b6b3141749ef8edfce743d39f61e59995 100644
--- a/src/client/inc/tscUtil.h
+++ b/src/client/inc/tscUtil.h
@@ -133,13 +133,13 @@ bool tscGroupbyColumn(SQueryInfo* pQueryInfo);
 bool tscIsTopbotQuery(SQueryInfo* pQueryInfo);
 int32_t tscGetTopbotQueryParam(SQueryInfo* pQueryInfo);
 
-bool tscNonOrderedProjectionQueryOnSTable(SQueryInfo *pQueryInfo, int32_t tableIndex);
-bool tscOrderedProjectionQueryOnSTable(SQueryInfo* pQueryInfo, int32_t tableIndex);
-bool tscIsProjectionQueryOnSTable(SQueryInfo* pQueryInfo, int32_t tableIndex);
+bool tscNonOrderedProjectionQueryOnSTable(SSqlCmd *pCmd, SQueryInfo *pQueryInfo, int32_t tableIndex);
+bool tscOrderedProjectionQueryOnSTable(SSqlCmd *pCmd, SQueryInfo* pQueryInfo, int32_t tableIndex);
+bool tscIsProjectionQueryOnSTable(SSqlCmd *pCmd, SQueryInfo* pQueryInfo, int32_t tableIndex);
 
 bool tscIsProjectionQuery(SQueryInfo* pQueryInfo);
 
-bool tscIsTwoStageSTableQuery(SQueryInfo* pQueryInfo, int32_t tableIndex);
+bool tscIsTwoStageSTableQuery(SSqlCmd *pCmd, SQueryInfo* pQueryInfo, int32_t tableIndex);
 bool tscQueryTags(SQueryInfo* pQueryInfo);
 bool tscMultiRoundQuery(SQueryInfo* pQueryInfo, int32_t tableIndex);
 bool tscQueryBlockInfo(SQueryInfo* pQueryInfo);
diff --git a/src/client/src/tscLocalMerge.c b/src/client/src/tscLocalMerge.c
index fd8d8428714041c1c2885c169e386f2b49e494c5..9511a10f88e6a2bdb29c55a391862e62d35aa661 100644
--- a/src/client/src/tscLocalMerge.c
+++ b/src/client/src/tscLocalMerge.c
@@ -300,7 +300,7 @@ void tscCreateLocalMerger(tExtMemBuffer **pMemBuffer, int32_t numOfBuffer, tOrde
   SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
 
   param->groupOrderType = pQueryInfo->groupbyExpr.orderType;
-  pReducer->orderPrjOnSTable = tscOrderedProjectionQueryOnSTable(pQueryInfo, 0);
+  pReducer->orderPrjOnSTable = tscOrderedProjectionQueryOnSTable(pCmd, pQueryInfo, 0);
 
   pRes->code = tLoserTreeCreate(&pReducer->pLoserTree, pReducer->numOfBuffer, param, treeComparator);
   if (pReducer->pLoserTree == NULL || pRes->code != 0) {
@@ -377,7 +377,7 @@ void tscCreateLocalMerger(tExtMemBuffer **pMemBuffer, int32_t numOfBuffer, tOrde
   pReducer->pDesc->pColumnModel->capacity = 1;
 
   // restore the limitation value at the last stage
-  if (tscOrderedProjectionQueryOnSTable(pQueryInfo, 0)) {
+  if (tscOrderedProjectionQueryOnSTable(pCmd, pQueryInfo, 0)) {
     pQueryInfo->limit.limit = pQueryInfo->clauseLimit;
     pQueryInfo->limit.offset = pQueryInfo->prjOffset;
   }
@@ -561,7 +561,7 @@ static int32_t createOrderDescriptor(tOrderDescriptor **pOrderDesc, SSqlCmd *pCm
   }
 
   // primary timestamp column is involved in final result
-  if (pQueryInfo->interval.interval != 0 || tscOrderedProjectionQueryOnSTable(pQueryInfo, 0)) {
+  if (pQueryInfo->interval.interval != 0 || tscOrderedProjectionQueryOnSTable(pCmd, pQueryInfo, 0)) {
     numOfGroupByCols++;
   }
 
@@ -751,6 +751,10 @@ int32_t tscLocalReducerEnvCreate(SSqlObj *pSql, tExtMemBuffer ***pMemBuffer, tOr
     if (functionId >= TSDB_FUNC_TS && functionId <= TSDB_FUNC_DIFF) {
       type = pModel->pFields[i].field.type;
       bytes = pModel->pFields[i].field.bytes;
+    } else if (functionId < 0) {
+      SUdfInfo* pUdfInfo = taosArrayGet(pCmd->pUdfInfo, -1 * functionId - 1);
+      type = pUdfInfo->resType;
+      bytes = pUdfInfo->resBytes;
     } else {
       if (functionId == TSDB_FUNC_FIRST_DST) {
         functionId = TSDB_FUNC_FIRST;
@@ -1082,6 +1086,10 @@ static void doExecuteFinalMerge(SSqlCmd *pCmd, SLocalMerger *pLocalMerge, bool n
     }
 
     pCtx->currentStage = MERGE_STAGE;
+    if (functionId < 0) {
+      continue;
+    }
+    
     if (needInit) {
       aAggs[pCtx->functionId].init(pCtx, pCtx->resultInfo);
     }
@@ -1093,7 +1101,24 @@ static void doExecuteFinalMerge(SSqlCmd *pCmd, SLocalMerger *pLocalMerge, bool n
       continue;
     }
 
-    aAggs[functionId].mergeFunc(&pLocalMerge->pCtx[j]);
+    if (functionId < 0) {
+      int32_t output = 0;
+
+      SUdfInfo* pUdfInfo = taosArrayGet(pCmd->pUdfInfo, -1 * functionId - 1);
+      assert (pUdfInfo->funcType == TSDB_UDF_TYPE_AGGREGATE);
+      
+      if (pUdfInfo->funcs[TSDB_UDF_FUNC_MERGE]) {
+        (*(udfMergeFunc)pUdfInfo->funcs[TSDB_UDF_FUNC_MERGE])(pLocalMerge->pCtx[j].pInput, pLocalMerge->pCtx[j].size, pLocalMerge->pCtx[j].pOutput, &output, &pUdfInfo->init);
+
+        // set the output value exist
+        pLocalMerge->pCtx[j].resultInfo->numOfRes = output;
+        if (output > 0) {
+          pLocalMerge->pCtx[j].resultInfo->hasResult = DATA_SET_FLAG;
+        }
+      }
+    } else {
+      aAggs[functionId].mergeFunc(&pLocalMerge->pCtx[j]);
+    }
   }
 }
 
@@ -1168,12 +1193,30 @@ static void fillMultiRowsOfTagsVal(SQueryInfo *pQueryInfo, int32_t numOfRes, SLo
   free(buf);
 }
 
-int32_t finalizeRes(SQueryInfo *pQueryInfo, SLocalMerger *pLocalMerge) {
+int32_t finalizeRes(SSqlCmd *pCmd, SQueryInfo *pQueryInfo, SLocalMerger *pLocalMerge) {
   size_t size = tscSqlExprNumOfExprs(pQueryInfo);
   
   for (int32_t k = 0; k < size; ++k) {
     SQLFunctionCtx* pCtx = &pLocalMerge->pCtx[k];
-    aAggs[pCtx->functionId].xFinalize(pCtx);
+
+    if (pCtx->functionId < 0) {
+      int32_t output = 0;
+
+      SUdfInfo* pUdfInfo = taosArrayGet(pCmd->pUdfInfo, -1 * pCtx->functionId - 1);
+      assert (pUdfInfo->funcType == TSDB_UDF_TYPE_AGGREGATE);
+    
+      if (pUdfInfo && pUdfInfo->funcs[TSDB_UDF_FUNC_FINALIZE]) {
+        (*(udfFinalizeFunc)pUdfInfo->funcs[TSDB_UDF_FUNC_FINALIZE])(pCtx->pOutput, &output, &pUdfInfo->init);
+
+        // set the output value exist
+        pCtx->resultInfo->numOfRes = output;
+        if (output > 0) {
+          pCtx->resultInfo->hasResult = DATA_SET_FLAG;
+        }
+      }    
+    } else {
+      aAggs[pCtx->functionId].xFinalize(pCtx);
+    }
   }
 
   pLocalMerge->hasPrevRow = false;
@@ -1192,13 +1235,13 @@ int32_t finalizeRes(SQueryInfo *pQueryInfo, SLocalMerger *pLocalMerge) {
  * results generated by simple aggregation function, we merge them all into one points
  * *Exception*: column projection query, required no merge procedure
  */
-bool needToMerge(SQueryInfo *pQueryInfo, SLocalMerger *pLocalMerge, tFilePage *tmpBuffer) {
+bool needToMerge(SSqlCmd *pCmd, SQueryInfo *pQueryInfo, SLocalMerger *pLocalMerge, tFilePage *tmpBuffer) {
   int32_t ret = 0;  // merge all result by default
 
   int16_t functionId = pLocalMerge->pCtx[0].functionId;
 
   // todo opt performance
-  if ((/*functionId == TSDB_FUNC_PRJ || */functionId == TSDB_FUNC_ARITHM) || (tscIsProjectionQueryOnSTable(pQueryInfo, 0) && pQueryInfo->distinctTag == false)) {  // column projection query
+  if ((/*functionId == TSDB_FUNC_PRJ || */functionId == TSDB_FUNC_ARITHM) || (tscIsProjectionQueryOnSTable(pCmd, pQueryInfo, 0) && pQueryInfo->distinctTag == false)) {  // column projection query
     ret = 1;                                                            // disable merge procedure
   } else {
     tOrderDescriptor *pDesc = pLocalMerge->pDesc;
@@ -1522,7 +1565,7 @@ int32_t tscDoLocalMerge(SSqlObj *pSql) {
     }
 
     if (pLocalMerge->hasPrevRow) {
-      if (needToMerge(pQueryInfo, pLocalMerge, tmpBuffer)) {
+      if (needToMerge(pCmd, pQueryInfo, pLocalMerge, tmpBuffer)) {
         // belong to the group of the previous row, continue process it
         doExecuteFinalMerge(pCmd, pLocalMerge, false);
 
@@ -1533,7 +1576,7 @@ int32_t tscDoLocalMerge(SSqlObj *pSql) {
          * current row does not belong to the group of previous row.
          * so the processing of previous group is completed.
          */
-        int32_t numOfRes = finalizeRes(pQueryInfo, pLocalMerge);
+        int32_t numOfRes = finalizeRes(pCmd, pQueryInfo, pLocalMerge);
         bool   sameGroup = isSameGroup(pCmd, pLocalMerge, pLocalMerge->prevRowOfInput, tmpBuffer);
 
         tFilePage *pResBuf = pLocalMerge->pResultBuf;
@@ -1605,7 +1648,7 @@ int32_t tscDoLocalMerge(SSqlObj *pSql) {
   }
 
   if (pLocalMerge->hasPrevRow) {
-    finalizeRes(pQueryInfo, pLocalMerge);
+    finalizeRes(pCmd, pQueryInfo, pLocalMerge);
   }
 
   if (pLocalMerge->pResultBuf->num) {
diff --git a/src/client/src/tscSQLParser.c b/src/client/src/tscSQLParser.c
index 6cdd186c28f5b1687d1557aa959125a4e48c5598..7ff2e832512f5c7297843cc55ae9c964a9a7067a 100644
--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@@ -5193,7 +5193,7 @@ int32_t parseOrderbyClause(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, SQuerySqlNode*
         pQueryInfo->order.orderColId = PRIMARYKEY_TIMESTAMP_COL_INDEX;
 
         // orderby ts query on super table
-        if (tscOrderedProjectionQueryOnSTable(pQueryInfo, 0)) {
+        if (tscOrderedProjectionQueryOnSTable(pCmd, pQueryInfo, 0)) {
           addPrimaryTsColIntoResult(pQueryInfo);
         }
       }
@@ -5817,13 +5817,13 @@ int32_t parseLimitClause(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, int32_t clauseIn
   // todo refactor
   if (UTIL_TABLE_IS_SUPER_TABLE(pTableMetaInfo)) {
     if (!tscQueryTags(pQueryInfo)) {  // local handle the super table tag query
-      if (tscIsProjectionQueryOnSTable(pQueryInfo, 0)) {
+      if (tscIsProjectionQueryOnSTable(pCmd, pQueryInfo, 0)) {
         if (pQueryInfo->slimit.limit > 0 || pQueryInfo->slimit.offset > 0) {
           return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg2);
         }
 
         // for projection query on super table, all queries are subqueries
-        if (tscNonOrderedProjectionQueryOnSTable(pQueryInfo, 0) &&
+        if (tscNonOrderedProjectionQueryOnSTable(pCmd, pQueryInfo, 0) &&
             !TSDB_QUERY_HAS_TYPE(pQueryInfo->type, TSDB_QUERY_TYPE_JOIN_QUERY)) {
           pQueryInfo->type |= TSDB_QUERY_TYPE_SUBQUERY;
         }
@@ -5859,7 +5859,7 @@ int32_t parseLimitClause(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, int32_t clauseIn
     pQueryInfo->prjOffset   = pQueryInfo->limit.offset;
     pQueryInfo->vgroupLimit = -1;
 
-    if (tscOrderedProjectionQueryOnSTable(pQueryInfo, 0)) {
+    if (tscOrderedProjectionQueryOnSTable(pCmd, pQueryInfo, 0)) {
       /*
        * the offset value should be removed during retrieve data from virtual node, since the
        * global order are done in client side, so the offset is applied at the client side
@@ -6462,7 +6462,7 @@ int32_t doFunctionsCompatibleCheck(SSqlCmd* pCmd, SQueryInfo* pQueryInfo) {
     }
 
     // projection query on super table does not compatible with "group by" syntax
-    if (tscNonOrderedProjectionQueryOnSTable(pQueryInfo, 0)) {
+    if (tscNonOrderedProjectionQueryOnSTable(pCmd, pQueryInfo, 0)) {
       return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg3);
     }
 
diff --git a/src/client/src/tscServer.c b/src/client/src/tscServer.c
index b94690f7fc2089ef996e8c8807b48e563ceb2f47..9ebd22d8425682c6483ad60ebc07b76abb0e2d3d 100644
--- a/src/client/src/tscServer.c
+++ b/src/client/src/tscServer.c
@@ -2485,7 +2485,7 @@ int tscProcessRetrieveRspFromNode(SSqlObj *pSql) {
     tscSetResRawPtr(pRes, pQueryInfo);
   } else if ((UTIL_TABLE_IS_CHILD_TABLE(pTableMetaInfo) || UTIL_TABLE_IS_NORMAL_TABLE(pTableMetaInfo)) && !TSDB_QUERY_HAS_TYPE(pQueryInfo->type, TSDB_QUERY_TYPE_SUBQUERY)) {
     tscSetResRawPtr(pRes, pQueryInfo);
-  } else if (tscNonOrderedProjectionQueryOnSTable(pQueryInfo, 0) && !TSDB_QUERY_HAS_TYPE(pQueryInfo->type, TSDB_QUERY_TYPE_JOIN_QUERY) && !TSDB_QUERY_HAS_TYPE(pQueryInfo->type, TSDB_QUERY_TYPE_JOIN_SEC_STAGE)) {
+  } else if (tscNonOrderedProjectionQueryOnSTable(pCmd, pQueryInfo, 0) && !TSDB_QUERY_HAS_TYPE(pQueryInfo->type, TSDB_QUERY_TYPE_JOIN_QUERY) && !TSDB_QUERY_HAS_TYPE(pQueryInfo->type, TSDB_QUERY_TYPE_JOIN_SEC_STAGE)) {
     tscSetResRawPtr(pRes, pQueryInfo);
   }
 
diff --git a/src/client/src/tscSql.c b/src/client/src/tscSql.c
index 93d0e9fd092b7e91fc8028e30f73a13bdb02627d..22ae192db1b8f9c84543c5bf331fd6e29c9e6600 100644
--- a/src/client/src/tscSql.c
+++ b/src/client/src/tscSql.c
@@ -560,7 +560,7 @@ static bool tscKillQueryInDnode(SSqlObj* pSql) {
 
   SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(pCmd, 0);
 
-  if ((pQueryInfo == NULL) || tscIsTwoStageSTableQuery(pQueryInfo, 0)) {
+  if ((pQueryInfo == NULL) || tscIsTwoStageSTableQuery(pCmd, pQueryInfo, 0)) {
     return true;
   }
 
@@ -673,7 +673,7 @@ static void tscKillSTableQuery(SSqlObj *pSql) {
 
   SQueryInfo* pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
 
-  if (!tscIsTwoStageSTableQuery(pQueryInfo, 0)) {
+  if (!tscIsTwoStageSTableQuery(pCmd, pQueryInfo, 0)) {
     return;
   }
 
@@ -724,7 +724,7 @@ void taos_stop_query(TAOS_RES *res) {
 
   SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
 
-  if (tscIsTwoStageSTableQuery(pQueryInfo, 0)) {
+  if (tscIsTwoStageSTableQuery(pCmd, pQueryInfo, 0)) {
     assert(pSql->rpcRid <= 0);
     tscKillSTableQuery(pSql);
   } else {
diff --git a/src/client/src/tscSubquery.c b/src/client/src/tscSubquery.c
index 299cf038057bf5ce80c449be41faa484e0a8ef93..2fd0b5e8bd948d4c6022fc8da46ac06bb0099659 100644
--- a/src/client/src/tscSubquery.c
+++ b/src/client/src/tscSubquery.c
@@ -23,6 +23,7 @@
 #include "tscSubquery.h"
 #include "tschemautil.h"
 #include "tsclient.h"
+#include "qUdf.h"
 #include "qUtil.h"
 
 typedef struct SInsertSupporter {
@@ -653,7 +654,7 @@ static int32_t tscLaunchRealSubqueries(SSqlObj* pSql) {
 
     if (UTIL_TABLE_IS_SUPER_TABLE(pTableMetaInfo)) {
       assert(pTableMetaInfo->pVgroupTables != NULL);
-      if (tscNonOrderedProjectionQueryOnSTable(pQueryInfo, 0)) {
+      if (tscNonOrderedProjectionQueryOnSTable(&pNew->cmd, pQueryInfo, 0)) {
         SArray* p = buildVgroupTableByResult(pQueryInfo, pTableMetaInfo->pVgroupTables);
         tscFreeVgroupTableInfo(pTableMetaInfo->pVgroupTables);
         pTableMetaInfo->pVgroupTables = p;
@@ -1442,7 +1443,7 @@ static void joinRetrieveFinalResCallback(void* param, TAOS_RES* tres, int numOfR
   }
 
   SSubqueryState* pState = &pParentSql->subState;
-  if (tscNonOrderedProjectionQueryOnSTable(pQueryInfo, 0) && numOfRows == 0) {
+  if (tscNonOrderedProjectionQueryOnSTable(pCmd, pQueryInfo, 0) && numOfRows == 0) {
     STableMetaInfo* pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
     assert(pQueryInfo->numOfTables == 1);
 
@@ -1479,7 +1480,7 @@ static void joinRetrieveFinalResCallback(void* param, TAOS_RES* tres, int numOfR
   }
 
   // update the records for each subquery in parent sql object.
-  bool stableQuery = tscIsTwoStageSTableQuery(pQueryInfo, 0);
+  bool stableQuery = tscIsTwoStageSTableQuery(pCmd, pQueryInfo, 0);
   for (int32_t i = 0; i < pState->numOfSub; ++i) {
     if (pParentSql->pSubs[i] == NULL) {
       tscDebug("%p %p sub:%d not retrieve data", pParentSql, NULL, i);
@@ -1576,7 +1577,7 @@ void tscFetchDatablockForSubquery(SSqlObj* pSql) {
       }
 
       SQueryInfo* p = tscGetQueryInfoDetail(&pSub->cmd, 0);
-      orderedPrjQuery = tscNonOrderedProjectionQueryOnSTable(p, 0);
+      orderedPrjQuery = tscNonOrderedProjectionQueryOnSTable(&pSub->cmd, p, 0);
       if (orderedPrjQuery) {
         break;
       }
@@ -1601,7 +1602,7 @@ void tscFetchDatablockForSubquery(SSqlObj* pSql) {
 
       SQueryInfo* pQueryInfo = tscGetQueryInfoDetail(&pSub->cmd, 0);
 
-      if (tscNonOrderedProjectionQueryOnSTable(pQueryInfo, 0) && pSub->res.row >= pSub->res.numOfRows &&
+      if (tscNonOrderedProjectionQueryOnSTable(&pSub->cmd, pQueryInfo, 0) && pSub->res.row >= pSub->res.numOfRows &&
           pSub->res.completed) {
         STableMetaInfo* pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
         assert(pQueryInfo->numOfTables == 1);
@@ -1804,7 +1805,7 @@ void tscJoinQueryCallback(void* param, TAOS_RES* tres, int code) {
   }
 
   // In case of consequence query from other vnode, do not wait for other query response here.
-  if (!(pTableMetaInfo->vgroupIndex > 0 && tscNonOrderedProjectionQueryOnSTable(pQueryInfo, 0))) {
+  if (!(pTableMetaInfo->vgroupIndex > 0 && tscNonOrderedProjectionQueryOnSTable(&pSql->cmd, pQueryInfo, 0))) {
     if (!subAndCheckDone(pSql, pParentSql, pSupporter->subqueryIndex)) {
       return;
     }      
@@ -1816,7 +1817,7 @@ void tscJoinQueryCallback(void* param, TAOS_RES* tres, int code) {
    * if the query is a continue query (vgroupIndex > 0 for projection query) for next vnode, do the retrieval of
    * data instead of returning to its invoker
    */
-  if (pTableMetaInfo->vgroupIndex > 0 && tscNonOrderedProjectionQueryOnSTable(pQueryInfo, 0)) {
+  if (pTableMetaInfo->vgroupIndex > 0 && tscNonOrderedProjectionQueryOnSTable(&pSql->cmd, pQueryInfo, 0)) {
     pSql->fp = joinRetrieveFinalResCallback;  // continue retrieve data
     pSql->cmd.command = TSDB_SQL_FETCH;
     
@@ -2791,6 +2792,22 @@ static void tscAllDataRetrievedFromDnode(SRetrieveSupport *trsupport, SSqlObj* p
   
   tscFreeRetrieveSup(pSql);
 
+  size_t size = tscSqlExprNumOfExprs(pQueryInfo);
+  for (int32_t j = 0; j < size; ++j) {
+    SQLFunctionCtx *pCtx = &pParentSql->res.pLocalMerger->pCtx[j];
+
+    int32_t functionId = pCtx->functionId;
+  
+    if (functionId < 0) {
+      SUdfInfo* pUdfInfo = taosArrayGet(pParentSql->cmd.pUdfInfo, -1 * functionId - 1);
+      int32_t code = initUdfInfo(pUdfInfo);
+      if (code != TSDB_CODE_SUCCESS) {
+        pParentSql->res.code = code;
+        tscAsyncResultOnError(pParentSql);
+      }
+    }
+  }
+
   // set the command flag must be after the semaphore been correctly set.
   pParentSql->cmd.command = TSDB_SQL_RETRIEVE_LOCALMERGE;
   if (pParentSql->res.code == TSDB_CODE_SUCCESS) {
@@ -2864,7 +2881,8 @@ static void tscRetrieveFromDnodeCallBack(void *param, TAOS_RES *tres, int numOfR
     tscDebug("%p sub:%p retrieve numOfRows:%d totalNumOfRows:%" PRIu64 " from ep:%s, orderOfSub:%d", pParentSql, pSql,
              pRes->numOfRows, pState->numOfRetrievedRows, pSql->epSet.fqdn[pSql->epSet.inUse], idx);
 
-    if (num > tsMaxNumOfOrderedResults && tscIsProjectionQueryOnSTable(pQueryInfo, 0)) {
+    SSqlCmd* pCmd = &pSql->cmd;
+    if (num > tsMaxNumOfOrderedResults && tscIsProjectionQueryOnSTable(pCmd, pQueryInfo, 0)) {
       tscError("%p sub:%p num of OrderedRes is too many, max allowed:%" PRId32 " , current:%" PRId64,
                pParentSql, pSql, tsMaxNumOfOrderedResults, num);
       tscAbortFurtherRetryRetrieval(trsupport, tres, TSDB_CODE_TSC_SORTED_RES_TOO_MANY);
@@ -3430,7 +3448,7 @@ static UNUSED_FUNC bool tscHasRemainDataInSubqueryResultSet(SSqlObj *pSql) {
   SSqlCmd *pCmd = &pSql->cmd;
   
   SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
-  if (tscNonOrderedProjectionQueryOnSTable(pQueryInfo, 0)) {
+  if (tscNonOrderedProjectionQueryOnSTable(pCmd, pQueryInfo, 0)) {
     bool allSubqueryExhausted = true;
     
     for (int32_t i = 0; i < pSql->subState.numOfSub; ++i) {
diff --git a/src/client/src/tscUtil.c b/src/client/src/tscUtil.c
index f5d616fef1c20fa6b5dd71cb46bfe60408070e38..58f4cb3fef9d4b87792f001d421b1c5b76f0ab2e 100644
--- a/src/client/src/tscUtil.c
+++ b/src/client/src/tscUtil.c
@@ -113,7 +113,7 @@ bool tscQueryBlockInfo(SQueryInfo* pQueryInfo) {
   return false;
 }
 
-bool tscIsTwoStageSTableQuery(SQueryInfo* pQueryInfo, int32_t tableIndex) {
+bool tscIsTwoStageSTableQuery(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, int32_t tableIndex) {
   if (pQueryInfo == NULL) {
     return false;
   }
@@ -128,7 +128,7 @@ bool tscIsTwoStageSTableQuery(SQueryInfo* pQueryInfo, int32_t tableIndex) {
   }
 
   // for ordered projection query, iterate all qualified vnodes sequentially
-  if (tscNonOrderedProjectionQueryOnSTable(pQueryInfo, tableIndex)) {
+  if (tscNonOrderedProjectionQueryOnSTable(pCmd, pQueryInfo, tableIndex)) {
     return false;
   }
 
@@ -139,7 +139,7 @@ bool tscIsTwoStageSTableQuery(SQueryInfo* pQueryInfo, int32_t tableIndex) {
   return false;
 }
 
-bool tscIsProjectionQueryOnSTable(SQueryInfo* pQueryInfo, int32_t tableIndex) {
+bool tscIsProjectionQueryOnSTable(SSqlCmd *pCmd, SQueryInfo* pQueryInfo, int32_t tableIndex) {
   STableMetaInfo* pTableMetaInfo = tscGetMetaInfo(pQueryInfo, tableIndex);
   
   /*
@@ -156,6 +156,15 @@ bool tscIsProjectionQueryOnSTable(SQueryInfo* pQueryInfo, int32_t tableIndex) {
   for (int32_t i = 0; i < numOfExprs; ++i) {
     int32_t functionId = tscSqlExprGet(pQueryInfo, i)->functionId;
 
+    if (functionId < 0) {
+      SUdfInfo* pUdfInfo = taosArrayGet(pCmd->pUdfInfo, -1 * functionId - 1);
+      if (pUdfInfo->funcType == TSDB_UDF_TYPE_AGGREGATE) {
+        return false;
+      }
+    
+      continue;
+    }
+        
     if (functionId != TSDB_FUNC_PRJ &&
         functionId != TSDB_FUNC_TAGPRJ &&
         functionId != TSDB_FUNC_TAG &&
@@ -171,8 +180,8 @@ bool tscIsProjectionQueryOnSTable(SQueryInfo* pQueryInfo, int32_t tableIndex) {
 }
 
 // not order by timestamp projection query on super table
-bool tscNonOrderedProjectionQueryOnSTable(SQueryInfo* pQueryInfo, int32_t tableIndex) {
-  if (!tscIsProjectionQueryOnSTable(pQueryInfo, tableIndex)) {
+bool tscNonOrderedProjectionQueryOnSTable(SSqlCmd *pCmd, SQueryInfo* pQueryInfo, int32_t tableIndex) {
+  if (!tscIsProjectionQueryOnSTable(pCmd, pQueryInfo, tableIndex)) {
     return false;
   }
   
@@ -180,8 +189,8 @@ bool tscNonOrderedProjectionQueryOnSTable(SQueryInfo* pQueryInfo, int32_t tableI
   return pQueryInfo->order.orderColId < 0;
 }
 
-bool tscOrderedProjectionQueryOnSTable(SQueryInfo* pQueryInfo, int32_t tableIndex) {
-  if (!tscIsProjectionQueryOnSTable(pQueryInfo, tableIndex)) {
+bool tscOrderedProjectionQueryOnSTable(SSqlCmd *pCmd, SQueryInfo* pQueryInfo, int32_t tableIndex) {
+  if (!tscIsProjectionQueryOnSTable(pCmd, pQueryInfo, tableIndex)) {
     return false;
   }
   
@@ -659,6 +668,30 @@ void*  tscDestroyBlockArrayList(SArray* pDataBlockList) {
   return NULL;
 }
 
+
+void freeUdfInfo(SUdfInfo* pUdfInfo) {
+  if (pUdfInfo == NULL) {
+    return;
+  }
+
+  if (pUdfInfo->funcs[TSDB_UDF_FUNC_DESTROY]) {
+    (*(udfDestroyFunc)pUdfInfo->funcs[TSDB_UDF_FUNC_DESTROY])(&pUdfInfo->init);
+  }
+  
+  tfree(pUdfInfo->name);
+
+  if (pUdfInfo->path) {
+    unlink(pUdfInfo->path);
+  }
+  
+  tfree(pUdfInfo->path);
+
+  tfree(pUdfInfo->content);
+  
+  taosCloseDll(pUdfInfo->handle);
+}
+
+
 void*  tscDestroyUdfArrayList(SArray* pUdfList) {
   if (pUdfList == NULL) {
     return NULL;
@@ -667,10 +700,7 @@ void*  tscDestroyUdfArrayList(SArray* pUdfList) {
   size_t size = taosArrayGetSize(pUdfList);
   for (int32_t i = 0; i < size; i++) {
     SUdfInfo* udf = taosArrayGet(pUdfList, i);
-    if (udf) {
-      tfree(udf->content);
-      tfree(udf->name);
-    }
+    freeUdfInfo(udf);
   }
 
   taosArrayDestroy(pUdfList);
@@ -2440,7 +2470,7 @@ void tscDoQuery(SSqlObj* pSql) {
         if (!TSDB_QUERY_HAS_TYPE(type, TSDB_QUERY_TYPE_JOIN_SEC_STAGE)) {
           tscProcessSql(pSql);
         } else { // secondary stage join query.
-          if (tscIsTwoStageSTableQuery(pQueryInfo, 0)) {  // super table query
+          if (tscIsTwoStageSTableQuery(pCmd, pQueryInfo, 0)) {  // super table query
             tscLockByThread(&pSql->squeryLock);
             tscHandleMasterSTableQuery(pSql);
             tscUnlockByThread(&pSql->squeryLock);
@@ -2454,7 +2484,7 @@ void tscDoQuery(SSqlObj* pSql) {
     } else if (tscMultiRoundQuery(pQueryInfo, 0) && pQueryInfo->round == 0) {
       tscHandleFirstRoundStableQuery(pSql);  // todo lock?
       return;
-    } else if (tscIsTwoStageSTableQuery(pQueryInfo, 0)) {  // super table query
+    } else if (tscIsTwoStageSTableQuery(pCmd, pQueryInfo, 0)) {  // super table query
       tscLockByThread(&pSql->squeryLock);
       tscHandleMasterSTableQuery(pSql);
       tscUnlockByThread(&pSql->squeryLock);
@@ -2619,7 +2649,7 @@ bool hasMoreVnodesToTry(SSqlObj* pSql) {
     numOfVgroups = (int32_t)taosArrayGetSize(pTableMetaInfo->pVgroupTables);
   }
 
-  return tscNonOrderedProjectionQueryOnSTable(pQueryInfo, 0) &&
+  return tscNonOrderedProjectionQueryOnSTable(pCmd, pQueryInfo, 0) &&
          (!tscHasReachLimitation(pQueryInfo, pRes)) && (pTableMetaInfo->vgroupIndex < numOfVgroups - 1);
 }
 
@@ -2637,7 +2667,7 @@ void tscTryQueryNextVnode(SSqlObj* pSql, __async_cb_func_t fp) {
    * no result returned from the current virtual node anymore, try the next vnode if exists
    * if case of: multi-vnode super table projection query
    */
-  assert(pRes->numOfRows == 0 && tscNonOrderedProjectionQueryOnSTable(pQueryInfo, 0) && !tscHasReachLimitation(pQueryInfo, pRes));
+  assert(pRes->numOfRows == 0 && tscNonOrderedProjectionQueryOnSTable(pCmd, pQueryInfo, 0) && !tscHasReachLimitation(pQueryInfo, pRes));
   STableMetaInfo* pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
   
   int32_t totalVgroups = pTableMetaInfo->vgroupList->numOfVgroups;
diff --git a/src/query/inc/qUdf.h b/src/query/inc/qUdf.h
index 7a1facebb199b339bbf556e368db02c9c20fa771..d141e5f8f3bb33d9cede79d3b4dfd767bbef21a6 100644
--- a/src/query/inc/qUdf.h
+++ b/src/query/inc/qUdf.h
@@ -16,7 +16,7 @@
 #ifndef TDENGINE_QUDF_H
 #define TDENGINE_QUDF_H
 
-enum { TSDB_UDF_FUNC_NORMAL = 0, TSDB_UDF_FUNC_INIT, TSDB_UDF_FUNC_FINALIZE, TSDB_UDF_FUNC_DESTROY, TSDB_UDF_FUNC_MAX_NUM };
+enum { TSDB_UDF_FUNC_NORMAL = 0, TSDB_UDF_FUNC_INIT, TSDB_UDF_FUNC_FINALIZE, TSDB_UDF_FUNC_MERGE, TSDB_UDF_FUNC_DESTROY, TSDB_UDF_FUNC_MAX_NUM };
 
 
 
@@ -43,16 +43,15 @@ typedef struct SUdfInfo {
   void   *handle;      // handle loaded in mem
   void   *funcs[TSDB_UDF_FUNC_MAX_NUM];     // function ptr
   SUdfInit init;
-  union {              // file path or [in memory] binary content
-    char *content;
-    char *path;
-  };
+  char *content;
+  char *path;
 } SUdfInfo;
 
 typedef void (*udfNormalFunc)(char* data, int16_t itype, int16_t iBytes, int32_t numOfRows, int64_t* ts, char* dataOutput, char* tsOutput,
-                        int32_t* numOfOutput, int16_t oType, int16_t oByte, SUdfInit* buf);
+                        int32_t* numOfOutput, int16_t oType, int16_t oBytes, SUdfInit* buf);
 typedef int32_t (*udfInitFunc)(SUdfInit* data);
 typedef void (*udfFinalizeFunc)(char* dataOutput, int32_t* numOfOutput, SUdfInit* buf);
+typedef void (*udfMergeFunc)(char* data, int32_t numOfRows, char* dataOutput, int32_t* numOfOutput, SUdfInit* buf);
 typedef void (*udfDestroyFunc)(SUdfInit* buf);
 
 
diff --git a/src/query/inc/qUtil.h b/src/query/inc/qUtil.h
index cdd8b0707a86404597fc1379e0743173734a1db1..87f2458658269296f129121af67ddb944c8c7770 100644
--- a/src/query/inc/qUtil.h
+++ b/src/query/inc/qUtil.h
@@ -90,4 +90,6 @@ int32_t getNumOfTotalRes(SGroupResInfo* pGroupResInfo);
 
 int32_t mergeIntoGroupResult(SGroupResInfo* pGroupResInfo, SQueryRuntimeEnv *pRuntimeEnv, int32_t* offset);
 
+int32_t initUdfInfo(SUdfInfo* pUdfInfo);
+
 #endif  // TDENGINE_QUERYUTIL_H
diff --git a/src/query/src/qExecutor.c b/src/query/src/qExecutor.c
index 005cf5ac4bf79fdfcfbb4407394e5dee10d32b2b..f11a0772c8a6fdf05c1e90789ea05967fe5bcf74 100644
--- a/src/query/src/qExecutor.c
+++ b/src/query/src/qExecutor.c
@@ -6008,6 +6008,8 @@ void destroyUdfInfo(SUdfInfo* pUdfInfo) {
   }
   
   tfree(pUdfInfo->path);
+
+  tfree(pUdfInfo->content);
   
   taosCloseDll(pUdfInfo->handle);
 
@@ -6027,6 +6029,9 @@ static char* getUdfFuncName(char* name, int type) {
     case TSDB_UDF_FUNC_FINALIZE:
       sprintf(funcname, "%s_finalize", name);
       break;
+    case TSDB_UDF_FUNC_MERGE:
+      sprintf(funcname, "%s_merge", name);
+      break;    
     case TSDB_UDF_FUNC_DESTROY:
       sprintf(funcname, "%s_destroy", name);
       break;
@@ -6038,7 +6043,7 @@ static char* getUdfFuncName(char* name, int type) {
   return funcname;
 }
 
-static int32_t initUdfInfo(SUdfInfo* pUdfInfo) {
+int32_t initUdfInfo(SUdfInfo* pUdfInfo) {
   if (pUdfInfo == NULL) {
     return TSDB_CODE_SUCCESS;
   }
@@ -6088,6 +6093,7 @@ static int32_t initUdfInfo(SUdfInfo* pUdfInfo) {
     
     if (pUdfInfo->funcType == TSDB_UDF_TYPE_AGGREGATE) {
       pUdfInfo->funcs[TSDB_UDF_FUNC_FINALIZE] = taosLoadSym(pUdfInfo->handle, getUdfFuncName(pUdfInfo->name, TSDB_UDF_FUNC_FINALIZE));
+      pUdfInfo->funcs[TSDB_UDF_FUNC_MERGE] = taosLoadSym(pUdfInfo->handle, getUdfFuncName(pUdfInfo->name, TSDB_UDF_FUNC_MERGE));
     }
 
     pUdfInfo->funcs[TSDB_UDF_FUNC_DESTROY] = taosLoadSym(pUdfInfo->handle, getUdfFuncName(pUdfInfo->name, TSDB_UDF_FUNC_DESTROY));
diff --git a/tests/script/sh/add_one.c b/tests/script/sh/add_one.c
index 4c1cb28a90581145a2be45fe2583eefacb935845..ec26f1dbd7df40327468ffc9827eb009e1b116ae 100644
--- a/tests/script/sh/add_one.c
+++ b/tests/script/sh/add_one.c
@@ -10,12 +10,12 @@ typedef struct SUdfInit{
  int const_item;       /* 0 if result is independent of arguments */
 } SUdfInit;
 
-void add_one(char* data, char type, int numOfRows, long long* ts, char* dataOutput, char* tsOutput,
-                        int* numOfOutput, SUdfInit* buf) {
+void add_one(char* data, short itype, short ibytes, int numOfRows, long long* ts, char* dataOutput, char* tsOutput,
+                        int* numOfOutput, short otype, short obytes, SUdfInit* buf) {
    int i;
    int r = 0;
-   printf("add_one input data:%p, type:%d, rows:%d, ts:%p,%lld, dataoutput:%p, tsOutput:%p, numOfOutput:%p, buf:%p\n", data, type, numOfRows, ts, *ts, dataOutput, tsOutput, numOfOutput, buf);
-   if (type == 4) {
+   printf("add_one input data:%p, type:%d, rows:%d, ts:%p,%lld, dataoutput:%p, tsOutput:%p, numOfOutput:%p, buf:%p\n", data, itype, numOfRows, ts, *ts, dataOutput, tsOutput, numOfOutput, buf);
+   if (itype == 4) {
      for(i=0;i<numOfRows;++i) {
        printf("input %d - %d", i, *((int *)data + i));
        *((int *)dataOutput+i)=*((int *)data + i) + 1;
diff --git a/tests/script/sh/sum_double.c b/tests/script/sh/sum_double.c
index 631564ba62d1676c1ada547e71378c37c053f82e..d814228d8a28f8b982673909a90fbcfbb2734d7c 100644
--- a/tests/script/sh/sum_double.c
+++ b/tests/script/sh/sum_double.c
@@ -35,27 +35,27 @@ void sum_double(char* data, short itype, short ibytes, int numOfRows, long long*
 void sum_double_finalize(char* dataOutput, int* numOfOutput, SUdfInit* buf) {
    int i;
    int r = 0;
-   printf("sum_double_finalize dataoutput:%p, numOfOutput:%p, buf:%p\n", dataOutput, numOfOutput, buf);
+   printf("sum_double_finalize dataoutput:%p:%d, numOfOutput:%d, buf:%p\n", dataOutput, *dataOutput, *numOfOutput, buf);
    *numOfOutput=1;
    *(int*)(buf->ptr)=*(int*)dataOutput*2;
    *(int*)dataOutput=*(int*)(buf->ptr);
    printf("sum_double finalize, dataoutput:%d, numOfOutput:%d\n", *(int *)dataOutput, *numOfOutput);
 }
 
-void sum_double_merge(char* dataOutput, int* numOfOutput, SUdfInit* buf) {
+void sum_double_merge(char* data, int32_t numOfRows, char* dataOutput, int32_t* numOfOutput, SUdfInit* buf) {
    int r = 0;
    int sum = 0;
    
-   printf("sum_double_merge dataoutput:%p, numOfOutput:%p, buf:%p\n", dataOutput, numOfOutput, buf);
-   for (int i = 0; i < *numOfOutput; ++i) {
-     printf("sum_double_merge %d - %d\n", i, *((int*)dataOutput + i));
-     sum +=*((int*)dataOutput + i);
+   printf("sum_double_merge dataoutput:%p, numOfOutput:%d, buf:%p\n", dataOutput, *numOfOutput, buf);
+   for (int i = 0; i < numOfRows; ++i) {
+     printf("sum_double_merge %d - %d\n", i, *((int*)data + i));
+     sum +=*((int*)data + i);
    }
    
-   *(int*)dataOutput=sum;
+   *(int*)dataOutput+=sum;
    *numOfOutput=1;
    
-   printf("sum_double sum_double_merge, dataoutput:%d, numOfOutput:%d\n", *(int *)dataOutput, *numOfOutput);
+   printf("sum_double_merge, dataoutput:%d, numOfOutput:%d\n", *(int *)dataOutput, *numOfOutput);
 }