diff --git a/src/client/src/tscSQLParser.c b/src/client/src/tscSQLParser.c
index fbe9172329c847ee9558cdd78c94ee21cc0f8b1e..548a280d9e5c565d015e5cf19ef9e5f0fcd284fc 100644
--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@@ -2820,6 +2820,32 @@ int32_t addExprAndResultField(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, int32_t col
 
         pExpr = tscExprAppend(pQueryInfo, functionId, &index, resultType, resultSize, getNewResColId(pCmd), interResult, false);
         tscExprAddParams(&pExpr->base, val, TSDB_DATA_TYPE_DOUBLE, sizeof(double));
+      } else if (functionId == TSDB_FUNC_MAVG || functionId == TSDB_FUNC_SAMPLE) {
+        tVariantDump(pVariant, val, TSDB_DATA_TYPE_BIGINT, true);
+
+        int64_t numRowsSelected = GET_INT32_VAL(val);
+        if (numRowsSelected <= 0 || numRowsSelected > 1000) {  // todo use macro
+          return invalidOperationMsg(tscGetErrorMsgPayload(pCmd), msg12);
+        }
+
+        // todo REFACTOR
+        // set the first column ts for top/bottom query
+        SColumnIndex index1 = {index.tableIndex, PRIMARYKEY_TIMESTAMP_COL_INDEX};
+        pExpr = tscExprAppend(pQueryInfo, TSDB_FUNC_TS_DUMMY, &index1, TSDB_DATA_TYPE_TIMESTAMP, TSDB_KEYSIZE, getNewResColId(pCmd),
+                              0, false);
+        tstrncpy(pExpr->base.aliasName, aAggs[TSDB_FUNC_TS_DUMMY].name, sizeof(pExpr->base.aliasName));
+
+        const int32_t TS_COLUMN_INDEX = PRIMARYKEY_TIMESTAMP_COL_INDEX;
+        SColumnList   ids = createColumnList(1, index.tableIndex, TS_COLUMN_INDEX);
+        insertResultField(pQueryInfo, colIndex, &ids, TSDB_KEYSIZE, TSDB_DATA_TYPE_TIMESTAMP,
+                          aAggs[TSDB_FUNC_TS_DUMMY].name, pExpr);
+
+        colIndex += 1;  // the first column is ts
+
+        getResultDataInfo(pSchema->type, pSchema->bytes, functionId, numRowsSelected, &resultType, &resultSize, &interResult, 0, false,
+                          pUdfInfo);
+        pExpr = tscExprAppend(pQueryInfo, functionId, &index, resultType, resultSize, getNewResColId(pCmd), interResult, false);
+        tscExprAddParams(&pExpr->base, val, TSDB_DATA_TYPE_BIGINT, sizeof(int64_t));
       } else {
         tVariantDump(pVariant, val, TSDB_DATA_TYPE_BIGINT, true);
 
@@ -2829,7 +2855,7 @@ int32_t addExprAndResultField(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, int32_t col
         }
 
         // todo REFACTOR
-        // set the first column ts for top/bottom/mavg/sample query
+        // set the first column ts for top/bottom query
         SColumnIndex index1 = {index.tableIndex, PRIMARYKEY_TIMESTAMP_COL_INDEX};
         pExpr = tscExprAppend(pQueryInfo, TSDB_FUNC_TS, &index1, TSDB_DATA_TYPE_TIMESTAMP, TSDB_KEYSIZE, getNewResColId(pCmd),
                                  0, false);
diff --git a/src/query/src/qAggMain.c b/src/query/src/qAggMain.c
index 886803d51adcb58a95ab205230c7c74d7c261830..3e01f7ed5abbb3f5b138db1f3cd46f55d85c6fa7 100644
--- a/src/query/src/qAggMain.c
+++ b/src/query/src/qAggMain.c
@@ -4678,7 +4678,7 @@ static void assignResultSample(SSampleFuncInfo *pInfo, int32_t index, int64_t ts
     tVariantCreateFromBinary(pInfo->values + index, pData, bytes, type);
   }
 
-  *(pInfo->timeStamps + pInfo->numSampled) = ts;
+  *(pInfo->timeStamps + index) = ts;
   return;
 }
 
@@ -4691,7 +4691,6 @@ static void do_reservoir_sample(SSampleFuncInfo *pInfo, int32_t samplesK, int64_
     int32_t j = rand() % (pInfo->totalPoints);
     if (j < samplesK) {
       assignResultSample(pInfo, j, ts, pData, bytes, type);
-      *(pInfo->timeStamps + j) = ts;
     }
   }
 }