diff --git a/src/client/src/tscFunctionImpl.c b/src/client/src/tscFunctionImpl.c
index edeca86c17f8d694ff5ace078ed79c1eef7a0781..d8ac0d3109fc207278882e365724879a8114897a 100644
--- a/src/client/src/tscFunctionImpl.c
+++ b/src/client/src/tscFunctionImpl.c
@@ -711,13 +711,16 @@ static int32_t firstDistFuncRequired(SQLFunctionCtx *pCtx, TSKEY start, TSKEY en
   if (pCtx->aOutputBuf == NULL) {
     return BLK_DATA_ALL_NEEDED;
   }
-  
-  SFirstLastInfo *pInfo = (SFirstLastInfo*) (pCtx->aOutputBuf + pCtx->inputBytes);
-  if (pInfo->hasResult != DATA_SET_FLAG) {
-    return BLK_DATA_ALL_NEEDED;
-  } else {  // data in current block is not earlier than current result
-    return (pInfo->ts <= start) ? BLK_DATA_NO_NEEDED : BLK_DATA_ALL_NEEDED;
-  }
+
+  return BLK_DATA_ALL_NEEDED;
+  // TODO pCtx->aOutputBuf is the previous windowRes output buffer, not current unloaded block. so the following filter
+  // is invalid
+//  SFirstLastInfo *pInfo = (SFirstLastInfo*) (pCtx->aOutputBuf + pCtx->inputBytes);
+//  if (pInfo->hasResult != DATA_SET_FLAG) {
+//    return BLK_DATA_ALL_NEEDED;
+//  } else {  // data in current block is not earlier than current result
+//    return (pInfo->ts <= start) ? BLK_DATA_NO_NEEDED : BLK_DATA_ALL_NEEDED;
+//  }
 }
 
 static int32_t lastDistFuncRequired(SQLFunctionCtx *pCtx, TSKEY start, TSKEY end, int32_t colId) {
@@ -730,12 +733,16 @@ static int32_t lastDistFuncRequired(SQLFunctionCtx *pCtx, TSKEY start, TSKEY end
     return BLK_DATA_ALL_NEEDED;
   }
 
-  SFirstLastInfo *pInfo = (SFirstLastInfo*) (pCtx->aOutputBuf + pCtx->inputBytes);
-  if (pInfo->hasResult != DATA_SET_FLAG) {
-    return BLK_DATA_ALL_NEEDED;
-  } else {
-    return (pInfo->ts > end) ? BLK_DATA_NO_NEEDED : BLK_DATA_ALL_NEEDED;
-  }
+  return BLK_DATA_ALL_NEEDED;
+  // TODO pCtx->aOutputBuf is the previous windowRes output buffer, not current unloaded block. so the following filter
+  // is invalid
+
+//  SFirstLastInfo *pInfo = (SFirstLastInfo*) (pCtx->aOutputBuf + pCtx->inputBytes);
+//  if (pInfo->hasResult != DATA_SET_FLAG) {
+//    return BLK_DATA_ALL_NEEDED;
+//  } else {
+//    return (pInfo->ts > end) ? BLK_DATA_NO_NEEDED : BLK_DATA_ALL_NEEDED;
+//  }
 }
 
 //////////////////////////////////////////////////////////////////////////////////////////////
diff --git a/src/client/src/tscSQLParser.c b/src/client/src/tscSQLParser.c
index 4bc793e79f2a35661ead7bfe6bdf4e4efc1b5d92..cceb876a06d65dcc07af5e8157aa27548fdc8f01 100644
--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@@ -351,7 +351,7 @@ int32_t tscToSQLCmd(SSqlObj* pSql, struct SSqlInfo* pInfo) {
     case TSDB_SQL_DESCRIBE_TABLE: {
       SStrToken*  pToken = &pInfo->pDCLInfo->a[0];
       const char* msg1 = "invalid table name";
-      const char* msg2 = "table name is too long";
+      const char* msg2 = "table name too long";
 
       if (tscValidateName(pToken) != TSDB_CODE_SUCCESS) {
         return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg1);
@@ -410,7 +410,6 @@ int32_t tscToSQLCmd(SSqlObj* pSql, struct SSqlInfo* pInfo) {
       const char* msg3 = "name too long";
 
       pCmd->command = pInfo->type;
-      // tDCLSQL* pDCL = pInfo->pDCLInfo;
 
       SUserInfo* pUser = &pInfo->pDCLInfo->user;
       SStrToken* pName = &pUser->user;
@@ -773,7 +772,7 @@ int32_t parseSlidingClause(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, SQuerySQL* pQu
 
 int32_t tscSetTableFullName(STableMetaInfo* pTableMetaInfo, SStrToken* pzTableName, SSqlObj* pSql) {
   const char* msg1 = "name too long";
-  const char* msg2 = "current database name is invalid";
+  const char* msg2 = "current database or database name invalid";
 
   SSqlCmd* pCmd = &pSql->cmd;
   int32_t  code = TSDB_CODE_SUCCESS;
@@ -6302,6 +6301,11 @@ int32_t doCheckForQuery(SSqlObj* pSql, SQuerySQL* pQuerySql, int32_t index) {
     }
 
     if (pQueryInfo->interval.interval > 0 && pQueryInfo->interval.intervalUnit != 'n' && pQueryInfo->interval.intervalUnit != 'y') {
+      bool initialWindows = TSWINDOW_IS_EQUAL(pQueryInfo->window, TSWINDOW_INITIALIZER);
+      if (initialWindows) {
+        return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg6);
+      }
+
       int64_t timeRange = ABS(pQueryInfo->window.skey - pQueryInfo->window.ekey);
       // number of result is not greater than 10,000,000
       if ((timeRange == 0) || (timeRange / pQueryInfo->interval.interval) > MAX_INTERVAL_TIME_WINDOW) {
diff --git a/src/query/inc/qResultbuf.h b/src/query/inc/qResultbuf.h
index 5303251d981f9e12bb92088b65cf6231d6e45f88..704df9f3f29cc0653c353ed194e02e72cb4c5fb2 100644
--- a/src/query/inc/qResultbuf.h
+++ b/src/query/inc/qResultbuf.h
@@ -73,12 +73,11 @@ typedef struct SDiskbasedResultBuf {
   bool      comp;                // compressed before flushed to disk
   int32_t   nextPos;             // next page flush position
 
-  const void*      handle;        // for debug purpose
+  const void*      handle;       // for debug purpose
   SResultBufStatis statis;
 } SDiskbasedResultBuf;
 
-#define DEFAULT_INTERN_BUF_PAGE_SIZE  (4096L)
-#define DEFAULT_INMEM_BUF_PAGES       10
+#define DEFAULT_INTERN_BUF_PAGE_SIZE  (256L)                          // in bytes
 #define PAGE_INFO_INITIALIZER         (SPageDiskInfo){-1, -1}
 
 /**
diff --git a/src/query/inc/qUtil.h b/src/query/inc/qUtil.h
index 314159484d0de1d161cdf183534a0bc1820fa90e..5320e5622e70a93c06edb4a1e5a3fe568498ef21 100644
--- a/src/query/inc/qUtil.h
+++ b/src/query/inc/qUtil.h
@@ -39,7 +39,6 @@ static FORCE_INLINE SWindowResult *getWindowResult(SWindowResInfo *pWindowResInf
 }
 
 #define curTimeWindowIndex(_winres)        ((_winres)->curIndex)
-#define GET_TIMEWINDOW(_winresInfo, _win)  (STimeWindow) {(_win)->skey, ((_win)->skey + (_winresInfo)->interval - 1)}
 #define GET_ROW_PARAM_FOR_MULTIOUTPUT(_q, tbq, sq) (((tbq) && (!sq))? (_q)->pSelectExpr[1].base.arg->argValue.i64:1)
 
 bool isWindowResClosed(SWindowResInfo *pWindowResInfo, int32_t slot);
diff --git a/src/query/inc/tsqlfunction.h b/src/query/inc/tsqlfunction.h
index a78bb7ec51de2886d5396a9a18192947221bce88..28b9a60102d41a11fa02fee1ca51cbf8e263bf3b 100644
--- a/src/query/inc/tsqlfunction.h
+++ b/src/query/inc/tsqlfunction.h
@@ -108,7 +108,7 @@ extern "C" {
 
 #define GET_FORWARD_DIRECTION_FACTOR(ord) (((ord) == TSDB_ORDER_ASC) ? QUERY_ASC_FORWARD_STEP : QUERY_DESC_FORWARD_STEP)
 
-#define MAX_INTERVAL_TIME_WINDOW 10000000
+#define MAX_INTERVAL_TIME_WINDOW 1000000  // maximum allowed time windows in final results
 #define TOP_BOTTOM_QUERY_LIMIT   100
 
 enum {
diff --git a/src/query/src/qExecutor.c b/src/query/src/qExecutor.c
index d3012e76624e641ce1e2051201761e52f0851f00..d3f44cdcc715bb236fafaa4947a54771052df307 100644
--- a/src/query/src/qExecutor.c
+++ b/src/query/src/qExecutor.c
@@ -187,7 +187,7 @@ static void setExecParams(SQuery *pQuery, SQLFunctionCtx *pCtx, void* inputData,
                           SDataStatis *pStatis, void *param, int32_t colIndex);
 
 static void initCtxOutputBuf(SQueryRuntimeEnv *pRuntimeEnv);
-static void destroyTableQueryInfo(STableQueryInfo *pTableQueryInfo);
+static void destroyTableQueryInfoImpl(STableQueryInfo *pTableQueryInfo);
 static void resetCtxOutputBuf(SQueryRuntimeEnv *pRuntimeEnv);
 static bool hasMainOutput(SQuery *pQuery);
 static void buildTagQueryResult(SQInfo *pQInfo);
@@ -782,6 +782,8 @@ static void doBlockwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, bool closed
   SQuery *        pQuery = pRuntimeEnv->pQuery;
   SQLFunctionCtx *pCtx = pRuntimeEnv->pCtx;
 
+  bool hasPrev = pCtx[0].preAggVals.isSet;
+
   if (IS_MASTER_SCAN(pRuntimeEnv) || closed) {
     for (int32_t k = 0; k < pQuery->numOfOutput; ++k) {
       pCtx[k].nStartQueryTimestamp = pWin->skey;
@@ -794,11 +796,17 @@ static void doBlockwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, bool closed
       }
 
       // not a whole block involved in query processing, statistics data can not be used
-      pCtx[k].preAggVals.isSet = (forwardStep == numOfTotal);
+      // NOTE: the original value of isSet have been changed here
+      if (pCtx[k].preAggVals.isSet && forwardStep < numOfTotal) {
+        pCtx[k].preAggVals.isSet = false;
+      }
 
       if (functionNeedToExecute(pRuntimeEnv, &pCtx[k], functionId)) {
         aAggs[functionId].xFunction(&pCtx[k]);
       }
+
+      // restore it
+      pCtx[k].preAggVals.isSet = hasPrev;
     }
   }
 }
@@ -1975,8 +1983,7 @@ static void changeExecuteScanOrder(SQInfo *pQInfo, SQueryTableMsg* pQueryMsg, bo
   // todo handle the case the the order irrelevant query type mixed up with order critical query type
   // descending order query for last_row query
   if (isFirstLastRowQuery(pQuery)) {
-    qDebug("QInfo:%p scan order changed for last_row query, old:%d, new:%d", GET_QINFO_ADDR(pQuery),
-           pQuery->order.order, TSDB_ORDER_ASC);
+    qDebug("QInfo:%p scan order changed for last_row query, old:%d, new:%d", pQInfo, pQuery->order.order, TSDB_ORDER_ASC);
 
     pQuery->order.order = TSDB_ORDER_ASC;
     if (pQuery->window.skey > pQuery->window.ekey) {
@@ -2078,13 +2085,14 @@ static int32_t getInitialPageNum(SQInfo *pQInfo) {
 
 static void getIntermediateBufInfo(SQueryRuntimeEnv* pRuntimeEnv, int32_t* ps, int32_t* rowsize) {
   SQuery* pQuery = pRuntimeEnv->pQuery;
+  int32_t MIN_ROWS_PER_PAGE = 4;
 
   *rowsize = (int32_t)(pQuery->rowSize * GET_ROW_PARAM_FOR_MULTIOUTPUT(pQuery, pRuntimeEnv->topBotQuery, pRuntimeEnv->stableQuery));
   int32_t overhead = sizeof(tFilePage);
 
   // one page contains at least two rows
   *ps = DEFAULT_INTERN_BUF_PAGE_SIZE;
-  while(((*rowsize) * 2) > (*ps) - overhead) {
+  while(((*rowsize) * MIN_ROWS_PER_PAGE) > (*ps) - overhead) {
     *ps = (*ps << 1u);
   }
 
@@ -3707,7 +3715,7 @@ static STableQueryInfo *createTableQueryInfo(SQueryRuntimeEnv *pRuntimeEnv, void
   return pTableQueryInfo;
 }
 
-void destroyTableQueryInfo(STableQueryInfo *pTableQueryInfo) {
+void destroyTableQueryInfoImpl(STableQueryInfo *pTableQueryInfo) {
   if (pTableQueryInfo == NULL) {
     return;
   }
@@ -4383,6 +4391,8 @@ static bool skipTimeInterval(SQueryRuntimeEnv *pRuntimeEnv, TSKEY* start) {
   return true;
 }
 
+static void doDestroyTableQueryInfo(STableGroupInfo* pTableqinfoGroupInfo);
+
 static int32_t setupQueryHandle(void* tsdb, SQInfo* pQInfo, bool isSTableQuery) {
   SQueryRuntimeEnv *pRuntimeEnv = &pQInfo->runtimeEnv;
   SQuery *pQuery = pQInfo->runtimeEnv.pQuery;
@@ -4422,16 +4432,20 @@ static int32_t setupQueryHandle(void* tsdb, SQInfo* pQInfo, bool isSTableQuery)
     // update the query time window
     pQuery->window = cond.twindow;
 
-    size_t numOfGroups = GET_NUM_OF_TABLEGROUP(pQInfo);
-    for(int32_t i = 0; i < numOfGroups; ++i) {
-      SArray *group = GET_TABLEGROUP(pQInfo, i);
+    if (pQInfo->tableGroupInfo.numOfTables == 0) {
+      pQInfo->tableqinfoGroupInfo.numOfTables = 0;
+    } else {
+      size_t numOfGroups = GET_NUM_OF_TABLEGROUP(pQInfo);
+      for(int32_t i = 0; i < numOfGroups; ++i) {
+        SArray *group = GET_TABLEGROUP(pQInfo, i);
 
-      size_t t = taosArrayGetSize(group);
-      for (int32_t j = 0; j < t; ++j) {
-        STableQueryInfo *pCheckInfo = taosArrayGetP(group, j);
+        size_t t = taosArrayGetSize(group);
+        for (int32_t j = 0; j < t; ++j) {
+          STableQueryInfo *pCheckInfo = taosArrayGetP(group, j);
 
-        pCheckInfo->win = pQuery->window;
-        pCheckInfo->lastKey = pCheckInfo->win.skey;
+          pCheckInfo->win = pQuery->window;
+          pCheckInfo->lastKey = pCheckInfo->win.skey;
+        }
       }
     }
   } else if (isPointInterpoQuery(pQuery)) {
@@ -6317,17 +6331,43 @@ _error:
 }
 
 static void freeColumnFilterInfo(SColumnFilterInfo* pFilter, int32_t numOfFilters) {
-    if (pFilter == NULL) {
+    if (pFilter == NULL || numOfFilters == 0) {
       return;
     }
+
     for (int32_t i = 0; i < numOfFilters; i++) {
       if (pFilter[i].filterstr) {
         free((void*)(pFilter[i].pz));
       }
     }
+
     free(pFilter);
 }
 
+static void doDestroyTableQueryInfo(STableGroupInfo* pTableqinfoGroupInfo) {
+  if (pTableqinfoGroupInfo->pGroupList != NULL) {
+    int32_t numOfGroups = (int32_t) taosArrayGetSize(pTableqinfoGroupInfo->pGroupList);
+    for (int32_t i = 0; i < numOfGroups; ++i) {
+      SArray *p = taosArrayGetP(pTableqinfoGroupInfo->pGroupList, i);
+
+      size_t num = taosArrayGetSize(p);
+      for(int32_t j = 0; j < num; ++j) {
+        STableQueryInfo* item = taosArrayGetP(p, j);
+        destroyTableQueryInfoImpl(item);
+      }
+
+      taosArrayDestroy(p);
+    }
+  }
+
+  taosArrayDestroy(pTableqinfoGroupInfo->pGroupList);
+  taosHashCleanup(pTableqinfoGroupInfo->map);
+
+  pTableqinfoGroupInfo->pGroupList = NULL;
+  pTableqinfoGroupInfo->map = NULL;
+  pTableqinfoGroupInfo->numOfTables = 0;
+}
+
 static void freeQInfo(SQInfo *pQInfo) {
   if (!isValidQInfo(pQInfo)) {
     return;
@@ -6388,25 +6428,9 @@ static void freeQInfo(SQInfo *pQInfo) {
     taosTFree(pQuery);
   }
 
-  // todo refactor, extract method to destroytableDataInfo
-  if (pQInfo->tableqinfoGroupInfo.pGroupList != NULL) {
-    int32_t numOfGroups = (int32_t)(GET_NUM_OF_TABLEGROUP(pQInfo));
-    for (int32_t i = 0; i < numOfGroups; ++i) {
-      SArray *p = GET_TABLEGROUP(pQInfo, i);
-
-      size_t num = taosArrayGetSize(p);
-      for(int32_t j = 0; j < num; ++j) {
-        STableQueryInfo* item = taosArrayGetP(p, j);
-        destroyTableQueryInfo(item);
-      }
-
-      taosArrayDestroy(p);
-    }
-  }
+  doDestroyTableQueryInfo(&pQInfo->tableqinfoGroupInfo);
 
   taosTFree(pQInfo->pBuf);
-  taosArrayDestroy(pQInfo->tableqinfoGroupInfo.pGroupList);
-  taosHashCleanup(pQInfo->tableqinfoGroupInfo.map);
   tsdbDestroyTableGroup(&pQInfo->tableGroupInfo);
   taosArrayDestroy(pQInfo->arrTableIdInfo);
 
diff --git a/src/query/src/qFill.c b/src/query/src/qFill.c
index 8660d9f4fe59b72aa88a058c922369d313e49b48..f186726c0120f2e2e34580fec0da00c2083e5da9 100644
--- a/src/query/src/qFill.c
+++ b/src/query/src/qFill.c
@@ -38,6 +38,9 @@ SFillInfo* taosInitFillInfo(int32_t order, TSKEY skey, int32_t numOfTags, int32_
   pFillInfo->numOfTags = numOfTags;
   pFillInfo->numOfCols = numOfCols;
   pFillInfo->precision = precision;
+
+  pFillInfo->interval.interval = slidingTime;
+  pFillInfo->interval.intervalUnit = slidingUnit;
   pFillInfo->interval.sliding = slidingTime;
   pFillInfo->interval.slidingUnit = slidingUnit;
 
diff --git a/src/tsdb/src/tsdbRead.c b/src/tsdb/src/tsdbRead.c
index 3a39d5fc49565958b849e1a913b4f1e3b8130ead..b18f45fca601435ba8e9315f4df835b2af113e4b 100644
--- a/src/tsdb/src/tsdbRead.c
+++ b/src/tsdb/src/tsdbRead.c
@@ -2707,4 +2707,5 @@ void tsdbDestroyTableGroup(STableGroupInfo *pGroupList) {
   }
 
   taosArrayDestroy(pGroupList->pGroupList);
+  pGroupList->numOfTables = 0;
 }
diff --git a/tests/pytest/client/twoClients.py b/tests/pytest/client/twoClients.py
new file mode 100644
index 0000000000000000000000000000000000000000..1a1b36c55438f8ea4050bb804b739be71c570960
--- /dev/null
+++ b/tests/pytest/client/twoClients.py
@@ -0,0 +1,96 @@
+###################################################################
+#           Copyright (c) 2016 by TAOS Technologies, Inc.
+#                     All rights reserved.
+#
+#  This file is proprietary and confidential to TAOS Technologies.
+#  No part of this file may be reproduced, stored, transmitted,
+#  disclosed or used in any form or by any means other than as
+#  expressly provided by the written permission from Jianhui Tao
+#
+###################################################################
+
+# -*- coding: utf-8 -*-
+
+import os
+import sys
+sys.path.insert(0, os.getcwd())
+from util.log import *
+from util.sql import *
+from util.dnodes import *
+import taos
+
+
+class TwoClients:
+    def initConnection(self):
+        self.host = "127.0.0.1"
+        self.user = "root"
+        self.password = "taosdata"
+        self.config = "/home/xp/git/TDengine/sim/dnode1/cfg"        
+    
+    def run(self):
+        tdDnodes.init("")
+        tdDnodes.setTestCluster(False)
+        tdDnodes.setValgrind(False)
+
+        tdDnodes.stopAll()
+        tdDnodes.deploy(1)
+        tdDnodes.start(1)
+        
+        # first client create a stable and insert data
+        conn1 = taos.connect(self.host, self.user, self.password, self.config)
+        cursor1 = conn1.cursor()
+        cursor1.execute("drop database if exists db")
+        cursor1.execute("create database db")
+        cursor1.execute("use db")
+        cursor1.execute("create table tb (ts timestamp, id int) tags(loc nchar(30))")
+        cursor1.execute("insert into t0 using tb tags('beijing') values(now, 1)")
+
+        # second client alter the table created by cleint
+        conn2 = taos.connect(self.host, self.user, self.password, self.config)
+        cursor2 = conn2.cursor() 
+        cursor2.execute("use db")       
+        cursor2.execute("alter table tb add column name nchar(30)")
+        
+        # first client should not be able to use the origin metadata
+        tdSql.init(cursor1, True)
+        tdSql.error("insert into t0 values(now, 2)")
+
+        # first client should be able to insert data with udpated medadata
+        tdSql.execute("insert into t0 values(now, 2, 'test')")
+        tdSql.query("select * from tb")
+        tdSql.checkRows(2)
+
+        # second client drop the table 
+        cursor2.execute("drop table t0")
+        cursor2.execute("create table t0 using tb tags('beijing')")
+
+        tdSql.execute("insert into t0 values(now, 2, 'test')")
+        tdSql.query("select * from tb")
+        tdSql.checkRows(1)
+
+        # error expected for two clients drop the same cloumn
+        cursor2.execute("alter table tb drop column name")
+        tdSql.error("alter table tb drop column name")
+
+        cursor2.execute("alter table tb add column speed int")
+        tdSql.error("alter table tb add column speed int")
+
+
+        tdSql.execute("alter table tb add column size int")
+        tdSql.query("describe tb")
+        tdSql.checkRows(5)
+        tdSql.checkData(0, 0, "ts")
+        tdSql.checkData(1, 0, "id")
+        tdSql.checkData(2, 0, "speed")
+        tdSql.checkData(3, 0, "size")
+        tdSql.checkData(4, 0, "loc")
+
+
+        cursor1.close()
+        cursor2.close()
+        conn1.close()
+        conn2.close()
+        
+clients = TwoClients()
+clients.initConnection()
+clients.run()
\ No newline at end of file
diff --git a/tests/pytest/fulltest.sh b/tests/pytest/fulltest.sh
index bfa546f92e6850cad1c4c070d149961221e41e22..c74fb33c3b67dd49abf2bf8f915d360216aa562f 100755
--- a/tests/pytest/fulltest.sh
+++ b/tests/pytest/fulltest.sh
@@ -187,6 +187,7 @@ python3 ./test.py -f functions/function_top.py
 #python3 ./test.py -f functions/function_twa.py
 python3 queryCount.py
 python3 ./test.py -f query/queryGroupbyWithInterval.py
+python3 client/twoClients.py 
 
 # tools
 python3 test.py -f tools/taosdemo.py
diff --git a/tests/script/general/parser/fill.sim b/tests/script/general/parser/fill.sim
index 488f807fbc710199fa7489cf67d010d3e12bcc9a..f89c27d71fd8ba02105f502afd4df26a1870ffb5 100644
--- a/tests/script/general/parser/fill.sim
+++ b/tests/script/general/parser/fill.sim
@@ -850,6 +850,8 @@ if $rows != 12 then
   return -1
 endi
 
+print =====================>td-1442
+sql_error select count(*) from m_fl_tb0 interval(1s) fill(prev);
 
 print =============== clear
 sql drop database $db
diff --git a/tests/script/general/parser/first_last_query.sim b/tests/script/general/parser/first_last_query.sim
index d11bdccb12066fb0d9249b3117f8b0dc00a5eca5..8127c1923015e130a85a98a50cd8d4bca23fedb3 100644
--- a/tests/script/general/parser/first_last_query.sim
+++ b/tests/script/general/parser/first_last_query.sim
@@ -65,22 +65,23 @@ endi
 if $data00 != @18-09-18 01:40:00.000@ then
   return -1   
 endi  
-#if $data01 != NULL then
+
 if $data01 != 999 then
   return -1   
-endi  
-#if $data02 != NULL then
+endi
+
 if $data02 != 999 then
   return -1  
-endi 
-#if $data03 != NULL then
+endi
+
 if $data03 != 999.00000 then
   return -1  
 endi    
-#if $data04 != NULL then
+
 if $data04 != 999.000000000 then
   return -1
 endi
+
 #if $data05 != NULL then
 if $data05 != 999 then
   return -1
@@ -127,7 +128,7 @@ if $data01 != 0 then
   return -1
 endi
 
-#add check for out of range first/last query
+print =============> add check for out of range first/last query
 sql select first(ts),last(ts) from first_tb4 where ts>'2018-9-18 1:40:01';
 if $row != 0 then
   return -1
@@ -136,4 +137,130 @@ endi
 sql select first(ts),last(ts) from first_tb4 where ts<'2018-9-17 8:50:0';
 if $row != 0 then
   return -1
+endi
+
+#first/last mix up query
+#select first(size),last(size) from stest interval(1d) group by tbname;
+print =====================>td-1477
+
+sql create table stest(ts timestamp,size INT,filenum INT) tags (appname binary(500),tenant binary(500));
+sql insert into test1 using stest tags('test1','aaa') values ('2020-09-04 16:53:54.003',210,3);
+sql insert into test2 using stest tags('test1','aaa') values ('2020-09-04 16:53:56.003',210,3);
+sql insert into test11 using stest tags('test11','bbb') values ('2020-09-04 16:53:57.003',210,3);
+sql insert into test12 using stest tags('test11','bbb') values ('2020-09-04 16:53:58.003',210,3);
+sql insert into test21 using stest tags('test21','ccc') values ('2020-09-04 16:53:59.003',210,3);
+sql insert into test22 using stest tags('test21','ccc') values ('2020-09-04 16:54:54.003',210,3);
+sql select sum(size) from stest group by appname;
+if $rows != 3 then
+  return -1
+endi
+
+if $data00 != 420 then
+  return -1
+endi
+if $data10 != 420 then
+  return -1
+endi
+if $data20 != 420 then
+  return -1
+endi
+
+if $data01 != @test1@ then
+return -1
+endi
+if $data11 != @test11@ then
+return -1
+endi
+if $data21 != @test21@ then
+return -1
+endi
+
+sql select sum(size) from stest interval(1d) group by appname;
+if $rows != 3 then
+ return -1
+endi
+
+#2020-09-04 00:00:00.000 |                   420 | test1                          |
+#2020-09-04 00:00:00.000 |                   420 | test11                         |
+#2020-09-04 00:00:00.000 |                   420 | test21                         |
+if $data00 != @20-09-04 00:00:00.000@ then
+ return -1
+endi
+
+if $data10 != @20-09-04 00:00:00.000@ then
+ return -1
+endi
+
+if $data20 != @20-09-04 00:00:00.000@ then
+ return -1
+endi
+
+if $data01 != 420 then
+ print expect 420 , actual $data01
+ return -1
+endi
+
+if $data11 != 420 then
+ return -1
+endi
+
+if $data21 != 420 then
+ return -1
+endi
+
+if $data02 != @test1@ then
+return -1
+endi
+if $data12 != @test11@ then
+return -1
+endi
+if $data22 != @test21@ then
+return -1
+endi
+
+print ===================>td-1477, one table has only one block occurs this bug.
+sql select first(size),count(*),LAST(SIZE) from stest where tbname in ('test1', 'test2') interval(1d) group by tbname;
+if $rows != 2 then
+ return -1
+endi
+
+if $data00 != @20-09-04 00:00:00.000@ then
+  return -1
+endi
+
+if $data01 != 210 then
+  return -1
+endi
+
+if $data02 != 1 then
+  return -1
+endi
+
+if $data03 != 210 then
+ return -1
+endi
+
+if $data04 != @test1@ then
+  return -1
+endi
+
+if $data10 != @20-09-04 00:00:00.000@ then
+  return -1
+endi
+
+if $data11 != 210 then
+  return -1
+endi
+
+if $data12 != 1 then
+  return -1
+endi
+
+if $data13 != 210 then
+ return -1
+endi
+
+if $data14 != @test2@ then
+  print expect test2 , actual: $data14
+  return -1
 endi
\ No newline at end of file
diff --git a/tests/script/general/parser/lastrow_query.sim b/tests/script/general/parser/lastrow_query.sim
index e9d8ce413dd6a4683019f70f3801cf2cc702c00d..f81a48d5b2d61ddf829920201dd01f5dd1ee44ba 100644
--- a/tests/script/general/parser/lastrow_query.sim
+++ b/tests/script/general/parser/lastrow_query.sim
@@ -218,4 +218,10 @@ endi
 if $data04 != 123.981000000 then
     print expect 123.981000000, actual: $data04
     return -1
+endi
+
+sql create table tu(ts timestamp, k int)
+sql select last_row(*) from tu
+if $row != 0 then
+  return -1
 endi
\ No newline at end of file