diff --git a/src/client/inc/tscUtil.h b/src/client/inc/tscUtil.h
index f77897a74b77dfc9d168698bde927197eee8e9cc..405a29943b6512f2408b670bc86f4b1792523eea 100644
--- a/src/client/inc/tscUtil.h
+++ b/src/client/inc/tscUtil.h
@@ -39,7 +39,6 @@ extern "C" {
 #define UTIL_TABLE_IS_NORMAL_TABLE(metaInfo)\
   (!(UTIL_TABLE_IS_SUPER_TABLE(metaInfo) || UTIL_TABLE_IS_CHILD_TABLE(metaInfo)))
 
-#define TSDB_COL_IS_TAG(f) (((f)&TSDB_COL_TAG) != 0)
 
 typedef struct SParsedColElem {
   int16_t colIndex;
diff --git a/src/client/inc/tsclient.h b/src/client/inc/tsclient.h
index d2c52e972af5aa65bc97497f93936187fc97164f..c15212d99b4d14a75f4700c98efcb863a51ba397 100644
--- a/src/client/inc/tsclient.h
+++ b/src/client/inc/tsclient.h
@@ -468,7 +468,7 @@ static FORCE_INLINE void tscGetResultColumnChr(SSqlRes* pRes, SFieldInfo* pField
   char* pData = pRes->data + pInfo->pSqlExpr->offset * pRes->numOfRows + bytes * pRes->row;
 
   // user defined constant value output columns
-  if (pInfo->pSqlExpr->colInfo.flag == TSDB_COL_UDC) {
+  if (TSDB_COL_IS_UD_COL(pInfo->pSqlExpr->colInfo.flag)) {
     if (type == TSDB_DATA_TYPE_NCHAR || type == TSDB_DATA_TYPE_BINARY) {
       pData = pInfo->pSqlExpr->param[1].pz;
       pRes->length[columnIndex] = pInfo->pSqlExpr->param[1].nLen;
diff --git a/src/client/src/tscFunctionImpl.c b/src/client/src/tscFunctionImpl.c
index e74fcba24618a539843532d60c838d4565b3fb1e..cf256ee616d626db989d6b362001dfede0c898af 100644
--- a/src/client/src/tscFunctionImpl.c
+++ b/src/client/src/tscFunctionImpl.c
@@ -1648,8 +1648,9 @@ static void last_function(SQLFunctionCtx *pCtx) {
   for (int32_t i = pCtx->size - 1; i >= 0; --i) {
     char *data = GET_INPUT_CHAR_INDEX(pCtx, i);
     if (pCtx->hasNull && isNull(data, pCtx->inputType)) {
-      continue;
+        continue; 
     }
+   
     
     memcpy(pCtx->aOutputBuf, data, pCtx->inputBytes);
     
@@ -1721,7 +1722,9 @@ static void last_dist_function(SQLFunctionCtx *pCtx) {
   for (int32_t i = pCtx->size - 1; i >= 0; --i) {
     char *data = GET_INPUT_CHAR_INDEX(pCtx, i);
     if (pCtx->hasNull && isNull(data, pCtx->inputType)) {
-      continue;
+      if (!pCtx->requireNull) {
+        continue; 
+      }
     }
     
     last_data_assign_impl(pCtx, data, i);
diff --git a/src/client/src/tscSQLParser.c b/src/client/src/tscSQLParser.c
index 5ce4c7125f3111cead393057e55e977e5cb6ede1..5cb08fb4a3bf5587cb325bc5cb07ce01982f4f38 100644
--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@@ -33,6 +33,8 @@
 
 #define DEFAULT_PRIMARY_TIMESTAMP_COL_NAME "_c0"
 
+#define TSWINDOW_IS_EQUAL(t1, t2) (((t1).skey == (t2).skey) && ((t1).ekey == (t2).ekey))
+
 // -1 is tbname column index, so here use the -3 as the initial value
 #define COLUMN_INDEX_INITIAL_VAL (-3)
 #define COLUMN_INDEX_INITIALIZER \
@@ -45,6 +47,10 @@ typedef struct SColumnList {  // todo refactor
   SColumnIndex ids[TSDB_MAX_COLUMNS];
 } SColumnList;
 
+typedef struct SConvertFunc {
+  int32_t originFuncId;
+  int32_t execFuncId;
+} SConvertFunc;
 static SSqlExpr* doAddProjectCol(SQueryInfo* pQueryInfo, int32_t outputIndex, int32_t colIndex, int32_t tableIndex);
 
 static int32_t setShowInfo(SSqlObj* pSql, SSqlInfo* pInfo);
@@ -1501,13 +1507,13 @@ int32_t addProjectionExprAndResultField(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, t
   return TSDB_CODE_SUCCESS;
 }
 
-static int32_t setExprInfoForFunctions(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, SSchema* pSchema, int32_t functionID, char* aliasName,
+static int32_t setExprInfoForFunctions(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, SSchema* pSchema, SConvertFunc cvtFunc, char* aliasName,
                                        int32_t resColIdx, SColumnIndex* pColIndex) {
   int16_t type = 0;
   int16_t bytes = 0;
-
   char        columnName[TSDB_COL_NAME_LEN] = {0};
   const char* msg1 = "not support column types";
+  int32_t functionID = cvtFunc.execFuncId;
 
   if (functionID == TSDB_FUNC_SPREAD) {
     if (pSchema[pColIndex->columnIndex].type == TSDB_DATA_TYPE_BINARY ||
@@ -1523,16 +1529,21 @@ static int32_t setExprInfoForFunctions(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, SS
     type = pSchema[pColIndex->columnIndex].type;
     bytes = pSchema[pColIndex->columnIndex].bytes;
   }
-
+  
   if (aliasName != NULL) {
     tstrncpy(columnName, aliasName, sizeof(columnName));
   } else {
-    getRevisedName(columnName, functionID, sizeof(columnName) - 1, pSchema[pColIndex->columnIndex].name);
+    getRevisedName(columnName, cvtFunc.originFuncId, sizeof(columnName) - 1, pSchema[pColIndex->columnIndex].name);
   }
   
+  
   SSqlExpr* pExpr = tscSqlExprAppend(pQueryInfo, functionID, pColIndex, type, bytes, bytes, false);
   tstrncpy(pExpr->aliasName, columnName, sizeof(pExpr->aliasName));
 
+  if (cvtFunc.originFuncId == TSDB_FUNC_LAST_ROW && cvtFunc.originFuncId != functionID) {
+    pExpr->colInfo.flag |= TSDB_COL_NULL;
+  }
+
   // set reverse order scan data blocks for last query
   if (functionID == TSDB_FUNC_LAST) {
     pExpr->numOfParams = 1;
@@ -1766,7 +1777,10 @@ int32_t addExprAndResultField(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, int32_t col
       if (changeFunctionID(optr, &functionID) != TSDB_CODE_SUCCESS) {
         return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg9);
       }
-
+      SConvertFunc cvtFunc = {.originFuncId = functionID, .execFuncId = functionID};
+      if (functionID == TSDB_FUNC_LAST_ROW && TSWINDOW_IS_EQUAL(pQueryInfo->window,TSWINDOW_INITIALIZER)) {
+        cvtFunc.execFuncId = TSDB_FUNC_LAST;
+      }
       if (!requireAllFields) {
         if (pItem->pNode->pParam->nExpr < 1) {
           return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg3);
@@ -1798,7 +1812,7 @@ int32_t addExprAndResultField(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, int32_t col
 
             for (int32_t j = 0; j < tscGetNumOfColumns(pTableMetaInfo->pTableMeta); ++j) {
               index.columnIndex = j;
-              if (setExprInfoForFunctions(pCmd, pQueryInfo, pSchema, functionID, pItem->aliasName, colIndex++, &index) != 0) {
+              if (setExprInfoForFunctions(pCmd, pQueryInfo, pSchema, cvtFunc, pItem->aliasName, colIndex++, &index) != 0) {
                 return TSDB_CODE_TSC_INVALID_SQL;
               }
             }
@@ -1815,8 +1829,7 @@ int32_t addExprAndResultField(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, int32_t col
             if ((index.columnIndex >= tscGetNumOfColumns(pTableMetaInfo->pTableMeta)) || (index.columnIndex < 0)) {
               return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg6);
             }
-
-            if (setExprInfoForFunctions(pCmd, pQueryInfo, pSchema, functionID, pItem->aliasName, colIndex + i, &index) != 0) {
+            if (setExprInfoForFunctions(pCmd, pQueryInfo, pSchema, cvtFunc, pItem->aliasName, colIndex + i, &index) != 0) {
               return TSDB_CODE_TSC_INVALID_SQL;
             }
 
@@ -1853,7 +1866,7 @@ int32_t addExprAndResultField(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, int32_t col
 
           for (int32_t i = 0; i < tscGetNumOfColumns(pTableMetaInfo->pTableMeta); ++i) {
             SColumnIndex index = {.tableIndex = j, .columnIndex = i};
-            if (setExprInfoForFunctions(pCmd, pQueryInfo, pSchema, functionID, pItem->aliasName, colIndex, &index) != 0) {
+            if (setExprInfoForFunctions(pCmd, pQueryInfo, pSchema, cvtFunc, pItem->aliasName, colIndex, &index) != 0) {
               return TSDB_CODE_TSC_INVALID_SQL;
             }
 
@@ -5238,7 +5251,7 @@ static bool tagColumnInGroupby(SSqlGroupbyExpr* pGroupbyExpr, int16_t columnId)
   for (int32_t j = 0; j < pGroupbyExpr->numOfGroupCols; ++j) {
     SColIndex* pColIndex = taosArrayGet(pGroupbyExpr->columnInfo, j);
   
-    if (columnId == pColIndex->colId && pColIndex->flag == TSDB_COL_TAG) {
+    if (columnId == pColIndex->colId && TSDB_COL_IS_TAG(pColIndex->flag )) {
       return true;
     }
   }
@@ -5537,7 +5550,6 @@ int32_t doFunctionsCompatibleCheck(SSqlCmd* pCmd, SQueryInfo* pQueryInfo) {
     return checkUpdateTagPrjFunctions(pQueryInfo, pCmd);
   }
 }
-
 int32_t doLocalQueryProcess(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, SQuerySQL* pQuerySql) {
   const char* msg1 = "only one expression allowed";
   const char* msg2 = "invalid expression in select clause";
@@ -6078,6 +6090,10 @@ int32_t doCheckForQuery(SSqlObj* pSql, SQuerySQL* pQuerySql, int32_t index) {
   }
 
   int32_t joinQuery = (pQuerySql->from != NULL && pQuerySql->from->nExpr > 2);
+
+  if (pQuerySql->pWhere) {
+    pQueryInfo->window = TSWINDOW_INITIALIZER;
+  }
   if (parseSelectClause(pCmd, index, pQuerySql->pSelection, isSTable, joinQuery) != TSDB_CODE_SUCCESS) {
     return TSDB_CODE_TSC_INVALID_SQL;
   }
diff --git a/src/inc/taosmsg.h b/src/inc/taosmsg.h
index 761a267ce53f9b2c54e0ea993ebd346564feee29..17e9c704f62984e15eb19e7876be554bea06dedb 100644
--- a/src/inc/taosmsg.h
+++ b/src/inc/taosmsg.h
@@ -170,6 +170,13 @@ enum _mgmt_table {
 #define TSDB_COL_NORMAL          0x0u    // the normal column of the table
 #define TSDB_COL_TAG             0x1u    // the tag column type
 #define TSDB_COL_UDC             0x2u    // the user specified normal string column, it is a dummy column
+#define TSDB_COL_NULL            0x4u    // the column filter NULL or not
+
+#define TSDB_COL_IS_TAG(f)    (((f&(~(TSDB_COL_NULL)))&TSDB_COL_TAG) != 0)
+#define TSDB_COL_IS_NORMAL_COL(f)    ((f&(~(TSDB_COL_NULL))) == TSDB_COL_NORMAL)
+#define TSDB_COL_IS_UD_COL(f)   ((f&(~(TSDB_COL_NULL))) == TSDB_COL_UDC)
+#define TSDB_COL_REQ_NULL(f) (((f)&TSDB_COL_NULL) != 0)
+
 
 extern char *taosMsg[];
 
diff --git a/src/query/inc/tsqlfunction.h b/src/query/inc/tsqlfunction.h
index 65ab82883b0a4a280e85bbaf66929081615795d3..384d8079a7533e68dea39ff7549f71ad4b748879 100644
--- a/src/query/inc/tsqlfunction.h
+++ b/src/query/inc/tsqlfunction.h
@@ -168,6 +168,7 @@ typedef struct SQLFunctionCtx {
   int16_t      outputType;
   int16_t      outputBytes;  // size of results, determined by function and input column data type
   bool         hasNull;      // null value exist in current block
+  bool         requireNull;    // require null in some function
   int16_t      functionId;   // function id
   void *       aInputElemBuf;
   char *       aOutputBuf;            // final result output buffer, point to sdata->data
diff --git a/src/query/src/qExecutor.c b/src/query/src/qExecutor.c
index 4e2e31d2694712b14ed6d526a1ee960c0163398b..02112664cb0c2def9a6c1e06d2dd1e57388fd6f2 100644
--- a/src/query/src/qExecutor.c
+++ b/src/query/src/qExecutor.c
@@ -35,9 +35,7 @@
  * forced to load primary column explicitly.
  */
 #define Q_STATUS_EQUAL(p, s)  (((p) & (s)) != 0)
-#define TSDB_COL_IS_TAG(f)    (((f)&TSDB_COL_TAG) != 0)
-#define TSDB_COL_IS_NORMAL_COL(f)    ((f) == TSDB_COL_NORMAL)
-#define TSDB_COL_IS_UD_COL(f)   ((f) == TSDB_COL_UDC)
+
 
 #define QUERY_IS_ASC_QUERY(q) (GET_FORWARD_DIRECTION_FACTOR((q)->order.order) == QUERY_ASC_FORWARD_STEP)
 
@@ -254,7 +252,7 @@ bool isGroupbyNormalCol(SSqlGroupbyExpr *pGroupbyExpr) {
 
   for (int32_t i = 0; i < pGroupbyExpr->numOfGroupCols; ++i) {
     SColIndex *pColIndex = taosArrayGet(pGroupbyExpr->columnInfo, i);
-    if (pColIndex->flag == TSDB_COL_NORMAL) {
+    if (TSDB_COL_IS_NORMAL_COL(pColIndex->flag)) {
       //make sure the normal column locates at the second position if tbname exists in group by clause
       if (pGroupbyExpr->numOfGroupCols > 1) {
         assert(pColIndex->colIndex > 0);
@@ -275,7 +273,7 @@ int16_t getGroupbyColumnType(SQuery *pQuery, SSqlGroupbyExpr *pGroupbyExpr) {
 
   for (int32_t i = 0; i < pGroupbyExpr->numOfGroupCols; ++i) {
     SColIndex *pColIndex = taosArrayGet(pGroupbyExpr->columnInfo, i);
-    if (pColIndex->flag == TSDB_COL_NORMAL) {
+    if (TSDB_COL_IS_NORMAL_COL(pColIndex->flag)) {
       colId = pColIndex->colId;
       break;
     }
@@ -1085,7 +1083,7 @@ static char *getGroupbyColumnData(SQuery *pQuery, int16_t *type, int16_t *bytes,
 
   for (int32_t k = 0; k < pGroupbyExpr->numOfGroupCols; ++k) {
     SColIndex* pColIndex = taosArrayGet(pGroupbyExpr->columnInfo, k);
-    if (pColIndex->flag == TSDB_COL_TAG) {
+    if (TSDB_COL_IS_TAG(pColIndex->flag)) {
       continue;
     }
 
@@ -1555,6 +1553,13 @@ static int32_t setupQueryRuntimeEnv(SQueryRuntimeEnv *pRuntimeEnv, int16_t order
     SQLFunctionCtx *pCtx = &pRuntimeEnv->pCtx[i];
     SColIndex* pIndex = &pSqlFuncMsg->colInfo;
 
+    if (TSDB_COL_REQ_NULL(pIndex->flag)) {
+      pCtx->requireNull = true; 
+      pIndex->flag &= ~(TSDB_COL_NULL); 
+    } else {
+      pCtx->requireNull = false; 
+    } 
+
     int32_t index = pSqlFuncMsg->colInfo.colIndex;
     if (TSDB_COL_IS_TAG(pIndex->flag)) {
       if (pIndex->colId == TSDB_TBNAME_COLUMN_INDEX) {  // todo refactor
@@ -1574,6 +1579,7 @@ static int32_t setupQueryRuntimeEnv(SQueryRuntimeEnv *pRuntimeEnv, int16_t order
       pCtx->inputType = pQuery->colList[index].type;
     }
 
+
     assert(isValidDataType(pCtx->inputType));
     pCtx->ptsOutputBuf = NULL;
 
@@ -1783,7 +1789,7 @@ static bool onlyQueryTags(SQuery* pQuery) {
     if (functionId != TSDB_FUNC_TAGPRJ &&
         functionId != TSDB_FUNC_TID_TAG &&
         (!(functionId == TSDB_FUNC_COUNT && pExprInfo->base.colInfo.colId == TSDB_TBNAME_COLUMN_INDEX)) &&
-        (!(functionId == TSDB_FUNC_PRJ && pExprInfo->base.colInfo.flag == TSDB_COL_UDC))) {
+        (!(functionId == TSDB_FUNC_PRJ && TSDB_COL_IS_UD_COL(pExprInfo->base.colInfo.flag)))) {
       return false;
     }
   }
@@ -5353,7 +5359,7 @@ static int32_t getColumnIndexInSource(SQueryTableMsg *pQueryMsg, SSqlFuncMsg *pE
       j += 1;
     }
 
-  } else if (pExprMsg->colInfo.flag == TSDB_COL_UDC) {  // user specified column data
+  } else if (TSDB_COL_IS_UD_COL(pExprMsg->colInfo.flag)) {  // user specified column data
     return TSDB_UD_COLUMN_INDEX;
   } else {
     while (j < pQueryMsg->numOfCols) {
@@ -5561,7 +5567,7 @@ static int32_t convertQueryMsg(SQueryTableMsg *pQueryMsg, SArray **pTableIdList,
 
     int16_t functionId = pExprMsg->functionId;
     if (functionId == TSDB_FUNC_TAG || functionId == TSDB_FUNC_TAGPRJ || functionId == TSDB_FUNC_TAG_DUMMY) {
-      if (pExprMsg->colInfo.flag != TSDB_COL_TAG) {  // ignore the column  index check for arithmetic expression.
+      if (!TSDB_COL_IS_TAG(pExprMsg->colInfo.flag)) {  // ignore the column  index check for arithmetic expression.
         code = TSDB_CODE_QRY_INVALID_MSG;
         goto _cleanup;
       }
@@ -6843,7 +6849,7 @@ static void buildTagQueryResult(SQInfo* pQInfo) {
       int16_t type = 0, bytes = 0;
       for(int32_t j = 0; j < pQuery->numOfOutput; ++j) {
         // not assign value in case of user defined constant output column
-        if (pExprInfo[j].base.colInfo.flag == TSDB_COL_UDC) {
+        if (TSDB_COL_IS_UD_COL(pExprInfo[j].base.colInfo.flag)) {
           continue;
         }
 
diff --git a/src/query/src/qFill.c b/src/query/src/qFill.c
index c1cfab3ea2c2ad9ed4d258f15930af8646d6f840..b13e32efbad9c501a778dab2986242e37b0d3eb0 100644
--- a/src/query/src/qFill.c
+++ b/src/query/src/qFill.c
@@ -55,7 +55,7 @@ SFillInfo* taosInitFillInfo(int32_t order, TSKEY skey, int32_t numOfTags, int32_
     SFillColInfo* pColInfo = &pFillInfo->pFillCol[i];
     pFillInfo->pData[i] = calloc(1, pColInfo->col.bytes * capacity);
 
-    if (pColInfo->flag == TSDB_COL_TAG) {
+    if (TSDB_COL_IS_TAG(pColInfo->flag)) {
       bool exists = false;
       for(int32_t j = 0; j < k; ++j) {
         if (pFillInfo->pTags[j].col.colId == pColInfo->col.colId) {
@@ -155,7 +155,7 @@ void taosFillCopyInputDataFromOneFilePage(SFillInfo* pFillInfo, tFilePage* pInpu
     char* data = pInput->data + pCol->col.offset * pInput->num;
     memcpy(pFillInfo->pData[i], data, (size_t)(pInput->num * pCol->col.bytes));
 
-    if (pCol->flag == TSDB_COL_TAG) {  // copy the tag value to tag value buffer
+    if (TSDB_COL_IS_TAG(pCol->flag)) {  // copy the tag value to tag value buffer
       for (int32_t j = 0; j < pFillInfo->numOfTags; ++j) {
         SFillTagColInfo* pTag = &pFillInfo->pTags[j];
         if (pTag->col.colId == pCol->col.colId) {
@@ -251,7 +251,7 @@ int taosDoLinearInterpolation(int32_t type, SPoint* point1, SPoint* point2, SPoi
 static void setTagsValue(SFillInfo* pFillInfo, tFilePage** data, int32_t num) {
   for(int32_t j = 0; j < pFillInfo->numOfCols; ++j) {
     SFillColInfo* pCol = &pFillInfo->pFillCol[j];
-    if (pCol->flag == TSDB_COL_NORMAL) {
+    if (TSDB_COL_IS_NORMAL_COL(pCol->flag)) {
       continue;
     }
 
@@ -446,7 +446,7 @@ int32_t generateDataBlockImpl(SFillInfo* pFillInfo, tFilePage** data, int32_t nu
         // assign rows to dst buffer
         for (int32_t i = 0; i < pFillInfo->numOfCols; ++i) {
           SFillColInfo* pCol = &pFillInfo->pFillCol[i];
-          if (pCol->flag == TSDB_COL_TAG) {
+          if (TSDB_COL_IS_TAG(pCol->flag)) {
             continue;
           }