diff --git a/src/client/src/tscGlobalmerge.c b/src/client/src/tscGlobalmerge.c
index 6acbfe3e8929c9a5a46ed0370f6cfb883988ef3e..14e426ee69f1b11fe09ef23d66190c75a2628e10 100644
--- a/src/client/src/tscGlobalmerge.c
+++ b/src/client/src/tscGlobalmerge.c
@@ -648,7 +648,8 @@ static void doExecuteFinalMerge(SOperatorInfo* pOperator, int32_t numOfExpr, SSD
 
         for(int32_t j = 0; j < numOfExpr; ++j) {
           pCtx[j].pOutput += (pCtx[j].outputBytes * numOfRows);
-          if (pCtx[j].functionId == TSDB_FUNC_TOP || pCtx[j].functionId == TSDB_FUNC_BOTTOM) {
+          if (pCtx[j].functionId == TSDB_FUNC_TOP || pCtx[j].functionId == TSDB_FUNC_BOTTOM ||
+              pCtx[j].functionId == TSDB_FUNC_SAMPLE) {
             if(j > 0) pCtx[j].ptsOutputBuf = pCtx[j - 1].pOutput;
           }
         }
diff --git a/src/client/src/tscSQLParser.c b/src/client/src/tscSQLParser.c
index 24b59d205f36bbdbb53d36dc9d8e47a67589acbf..c90f6062b7c274f26de64fcb8bf9681d0a9ee882 100644
--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@@ -3343,7 +3343,8 @@ int32_t tscTansformFuncForSTableQuery(SQueryInfo* pQueryInfo) {
     
     if ((functionId >= TSDB_FUNC_SUM && functionId <= TSDB_FUNC_TWA) ||
         (functionId >= TSDB_FUNC_FIRST_DST && functionId <= TSDB_FUNC_STDDEV_DST) ||
-        (functionId >= TSDB_FUNC_RATE && functionId <= TSDB_FUNC_IRATE)) {
+        (functionId >= TSDB_FUNC_RATE && functionId <= TSDB_FUNC_IRATE) ||
+        (functionId == TSDB_FUNC_SAMPLE)) {
       if (getResultDataInfo(pSrcSchema->type, pSrcSchema->bytes, functionId, (int32_t)pExpr->base.param[0].i64, &type, &bytes,
                             &interBytes, 0, true, NULL) != TSDB_CODE_SUCCESS) {
         return TSDB_CODE_TSC_INVALID_OPERATION;
diff --git a/src/query/inc/qAggMain.h b/src/query/inc/qAggMain.h
index de0ed97db8dbb87db159aeb5dbc6d52885b7ac59..e3e5ccbce9f5c49871a7f0f5378fc56845e1b410 100644
--- a/src/query/inc/qAggMain.h
+++ b/src/query/inc/qAggMain.h
@@ -74,9 +74,7 @@ extern "C" {
 #define TSDB_FUNC_ROUND        35
 
 #define TSDB_FUNC_CSUM         36
-
 #define TSDB_FUNC_MAVG         37
-
 #define TSDB_FUNC_SAMPLE       38
 
 #define TSDB_FUNC_BLKINFO      39
diff --git a/src/query/src/qAggMain.c b/src/query/src/qAggMain.c
index 32c8630ff2ff04bb6fe453aebf49344adea6fc7a..f8fd18d90a38b18f49e6822e9c1c666a2553c4fa 100644
--- a/src/query/src/qAggMain.c
+++ b/src/query/src/qAggMain.c
@@ -183,7 +183,8 @@ typedef struct {
 typedef struct  {
   int32_t totalPoints;
   int32_t numSampled;
-  tVariant *values;
+  int16_t colBytes;
+  char *values;
   int64_t *timeStamps;
 } SSampleFuncInfo;
 
@@ -276,14 +277,6 @@ int32_t getResultDataInfo(int32_t dataType, int32_t dataBytes, int32_t functionI
     return TSDB_CODE_SUCCESS;
   }
 
-  if (functionId == TSDB_FUNC_SAMPLE) {
-    *type = (int16_t)dataType;
-    *bytes = (int16_t)dataBytes;
-    size_t size = sizeof(SSampleFuncInfo) + sizeof(tVariant) *  param + sizeof(int64_t) * param;
-    *interBytes = (int32_t)size;
-    return TSDB_CODE_SUCCESS;
-  }
-
   if (isSuperTable) {
     if (functionId < 0) {
       if (pUdfInfo->bufSize > 0) {
@@ -328,6 +321,10 @@ int32_t getResultDataInfo(int32_t dataType, int32_t dataBytes, int32_t functionI
       *interBytes = *bytes;
       
       return TSDB_CODE_SUCCESS;
+    } else if (functionId == TSDB_FUNC_SAMPLE) {
+      *type = TSDB_DATA_TYPE_BINARY;
+      *bytes = (int16_t)(sizeof(SSampleFuncInfo) + sizeof(dataBytes) *  param + sizeof(int64_t) * param);
+      *interBytes = *bytes;
     } else if (functionId == TSDB_FUNC_SPREAD) {
       *type = TSDB_DATA_TYPE_BINARY;
       *bytes = sizeof(SSpreadInfo);
@@ -436,6 +433,11 @@ int32_t getResultDataInfo(int32_t dataType, int32_t dataBytes, int32_t functionI
     
     // the output column may be larger than sizeof(STopBotInfo)
     *interBytes = (int32_t)size;
+  } else if (functionId == TSDB_FUNC_SAMPLE) {
+      *type = (int16_t)dataType;
+      *bytes = (int16_t)dataBytes;
+      size_t size = sizeof(SSampleFuncInfo) + sizeof(dataBytes) *  param + sizeof(int64_t) * param;
+      *interBytes = (int32_t)size;
   } else if (functionId == TSDB_FUNC_LAST_ROW) {
     *type = (int16_t)dataType;
     *bytes = (int16_t)dataBytes;
@@ -4669,15 +4671,19 @@ static void mavg_function(SQLFunctionCtx *pCtx) {
 //////////////////////////////////////////////////////////////////////////////////
 // Sample function with reservoir sampling algorithm
 
-static void assignResultSample(SSampleFuncInfo *pInfo, int32_t index, int64_t ts, void *pData, uint16_t type, int16_t bytes) {
-  if (type == TSDB_DATA_TYPE_BINARY || type == TSDB_DATA_TYPE_NCHAR) {
-    int32_t maxLen = bytes - VARSTR_HEADER_SIZE;
-    int32_t len = (varDataLen(pData) > maxLen)? maxLen:varDataLen(pData);
-    tVariantCreateFromBinary(pInfo->values + index, varDataVal(pData), len, type);
-  } else {
-    tVariantCreateFromBinary(pInfo->values + index, pData, bytes, type);
+static SSampleFuncInfo* getSampleFuncOutputInfo(SQLFunctionCtx *pCtx) {
+  SResultRowCellInfo *pResInfo = GET_RES_INFO(pCtx);
+
+  // only the first_stage stable is directly written data into final output buffer
+  if (pCtx->stableQuery && pCtx->currentStage != MERGE_STAGE) {
+    return (SSampleFuncInfo *) pCtx->pOutput;
+  } else { // during normal table query and super table at the secondary_stage, result is written to intermediate buffer
+    return GET_ROWCELL_INTERBUF(pResInfo);
   }
+}
 
+static void assignResultSample(SSampleFuncInfo *pInfo, int32_t index, int64_t ts, void *pData, uint16_t type, int16_t bytes) {
+  assignVal(pInfo->values + index*bytes, pData, bytes, type);
   *(pInfo->timeStamps + index) = ts;
   return;
 }
@@ -4702,8 +4708,7 @@ static void copySampleFuncRes(SQLFunctionCtx *pCtx, int32_t type) {
   TSKEY* pTimestamp = pCtx->ptsOutputBuf;
   char* pOutput = pCtx->pOutput;
   for (int32_t i = 0; i < pRes->numSampled; ++i) {
-
-    tVariantDump(pRes->values + i, (char*)pOutput, type, true);
+    assignVal(pOutput, pRes->values + i*pCtx->inputBytes, pRes->colBytes, type);
     *pTimestamp = *(pRes->timeStamps + i);
 
     pOutput += pCtx->outputBytes;
@@ -4719,11 +4724,12 @@ static bool sample_function_setup(SQLFunctionCtx *pCtx, SResultRowCellInfo* pRes
 
   srand(taosSafeRand());
 
-  SSampleFuncInfo *pRes = GET_ROWCELL_INTERBUF(pResInfo);
+  SSampleFuncInfo *pRes = getSampleFuncOutputInfo(pCtx);
   pRes->totalPoints = 0;
   pRes->numSampled = 0;
-  pRes->values = (tVariant*) ((char*)pRes + sizeof(SSampleFuncInfo));
-  pRes->timeStamps = (int64_t*)((char*)pRes->values + sizeof(tVariant) * pCtx->param[0].i64);
+  pRes->values = ((char*)pRes + sizeof(SSampleFuncInfo));
+  pRes->colBytes = (pCtx->currentStage != MERGE_STAGE) ? pCtx->inputBytes : pCtx->outputBytes;
+  pRes->timeStamps = (int64_t *)((char *)pRes->values + pRes->colBytes * pCtx->param[0].i64);
   return true;
 }
 
@@ -4731,11 +4737,11 @@ static void sample_function(SQLFunctionCtx *pCtx) {
   int32_t notNullElems = 0;
 
   SResultRowCellInfo *pResInfo = GET_RES_INFO(pCtx);
-  SSampleFuncInfo *pRes = GET_ROWCELL_INTERBUF(pResInfo);
+  SSampleFuncInfo *pRes = getSampleFuncOutputInfo(pCtx);
 
-  if (pRes->values != (tVariant*) ((char*)pRes + sizeof(SSampleFuncInfo))) {
-    pRes->values = (tVariant*) ((char*)pRes + sizeof(SSampleFuncInfo));
-    pRes->timeStamps = (int64_t*)((char*)pRes->values + sizeof(tVariant) * pCtx->param[0].i64);
+  if (pRes->values !=  ((char*)pRes + sizeof(SSampleFuncInfo))) {
+    pRes->values =  ((char*)pRes + sizeof(SSampleFuncInfo));
+    pRes->timeStamps = (int64_t*)((char*)pRes->values + pRes->colBytes * pCtx->param[0].i64);
   }
 
   for (int32_t i = 0; i < pCtx->size; ++i) {
@@ -4747,7 +4753,7 @@ static void sample_function(SQLFunctionCtx *pCtx) {
     notNullElems++;
 
     TSKEY ts = (pCtx->ptsList != NULL)? GET_TS_DATA(pCtx, i):0;
-    do_reservoir_sample(pRes, (int32_t)pCtx->param[0].i64, ts, data, pCtx->inputType, pCtx->inputBytes);
+    do_reservoir_sample(pRes, (int32_t)pCtx->param[0].i64, ts, data, pCtx->inputType, pRes->colBytes);
   }
 
   if (!pCtx->hasNull) {
@@ -4762,6 +4768,23 @@ static void sample_function(SQLFunctionCtx *pCtx) {
   }
 }
 
+static void sample_func_merge(SQLFunctionCtx *pCtx) {
+  SSampleFuncInfo* pInput = (SSampleFuncInfo*)GET_INPUT_DATA_LIST(pCtx);
+  pInput->values = ((char*)pInput + sizeof(SSampleFuncInfo));
+  pInput->timeStamps = (int64_t*)((char*)pInput->values + pInput->colBytes * pCtx->param[0].i64);
+
+  SSampleFuncInfo *pOutput = getSampleFuncOutputInfo(pCtx);
+  for (int32_t i = 0; i < pInput->numSampled; ++i) {
+    assignResultSample(pOutput, i, pInput->timeStamps[i],
+                       pInput->values + i * pInput->colBytes, pCtx->outputType, pInput->colBytes);
+  }
+
+  SET_VAL(pCtx, pInput->numSampled, pOutput->numSampled);
+  if (pOutput->numSampled > 0) {
+    SResultRowCellInfo *pResInfo = GET_RES_INFO(pCtx);
+    pResInfo->hasResult = DATA_SET_FLAG;
+  }
+}
 
 static void sample_func_finalizer(SQLFunctionCtx *pCtx) {
   SResultRowCellInfo *pResInfo = GET_RES_INFO(pCtx);
@@ -4775,10 +4798,6 @@ static void sample_func_finalizer(SQLFunctionCtx *pCtx) {
   GET_TRUE_DATA_TYPE();
   copySampleFuncRes(pCtx, type);
 
-  for (int32_t i = 0; i < pRes->numSampled; ++i) {
-    tVariantDestroy(pRes->values + i);
-  }
-
   doFinalizer(pCtx);
 }
 
@@ -5266,12 +5285,12 @@ SAggFunctionInfo aAggs[] = {{
                               // 38
                               "sample",
                               TSDB_FUNC_SAMPLE,
-                              TSDB_FUNC_INVALID_ID,
+                              TSDB_FUNC_SAMPLE,
                               TSDB_FUNCSTATE_MO | TSDB_FUNCSTATE_STABLE | TSDB_FUNCSTATE_NEED_TS | TSDB_FUNCSTATE_SELECTIVITY,
                               sample_function_setup,
                               sample_function,
                               sample_func_finalizer,
-                              noop1,
+                              sample_func_merge,
                               dataBlockRequired,
                           },
                           {