diff --git a/source/common/src/tdatablock.c b/source/common/src/tdatablock.c
index 33dc3a2469d79fab1035731cfeb5178f5c7a26d1..44d261bd3145b2760a215611c31dd20dc5b8d4d9 100644
--- a/source/common/src/tdatablock.c
+++ b/source/common/src/tdatablock.c
@@ -192,6 +192,9 @@ int32_t colDataMergeCol(SColumnInfoData* pColumnInfoData, uint32_t numOfRow1, co
     return numOfRow1;
   }
 
+  if (pSource->hasNull) {
+    pColumnInfoData->hasNull = pSource->hasNull;
+  }
   if (IS_VAR_DATA_TYPE(pColumnInfoData->info.type)) {
     // Handle the bitmap
     char* p = taosMemoryRealloc(pColumnInfoData->varmeta.offset, sizeof(int32_t) * (numOfRow1 + numOfRow2));
@@ -313,9 +316,9 @@ int32_t blockDataUpdateTsWindow(SSDataBlock* pDataBlock) {
 }
 
 int32_t blockDataMerge(SSDataBlock* pDest, const SSDataBlock* pSrc) {
-  assert(pSrc != NULL && pDest != NULL && pDest->info.numOfCols == pSrc->info.numOfCols);
+  assert(pSrc != NULL && pDest != NULL);
 
-  int32_t numOfCols = pSrc->info.numOfCols;
+  int32_t numOfCols = pDest->info.numOfCols;
   for (int32_t i = 0; i < numOfCols; ++i) {
     SColumnInfoData* pCol2 = taosArrayGet(pDest->pDataBlock, i);
     SColumnInfoData* pCol1 = taosArrayGet(pSrc->pDataBlock, i);
diff --git a/source/libs/executor/inc/tsort.h b/source/libs/executor/inc/tsort.h
index 3c7194de6fdea10548ab46dbb07503076d7a7f03..03bbe8098c0008d5122fdf7c1e1be823e3003559 100644
--- a/source/libs/executor/inc/tsort.h
+++ b/source/libs/executor/inc/tsort.h
@@ -52,6 +52,11 @@ typedef struct SMsortComparParam {
   SArray       *orderInfo;   // SArray<SBlockOrderInfo>
 } SMsortComparParam;
 
+struct STupleHandle {
+  SSDataBlock* pBlock;
+  int32_t      rowIndex;
+};
+
 typedef struct SSortHandle SSortHandle;
 typedef struct STupleHandle STupleHandle;
 
diff --git a/source/libs/executor/src/executorimpl.c b/source/libs/executor/src/executorimpl.c
index 4cc1658e6454da698b8595efa56cc8bb9cba9c90..48b734f3aa14427ec708036210b1762eb53feb41 100644
--- a/source/libs/executor/src/executorimpl.c
+++ b/source/libs/executor/src/executorimpl.c
@@ -302,10 +302,6 @@ SSDataBlock* createOutputBuf_rv1(SDataBlockDescNode* pNode) {
     }
 
     taosArrayPush(pBlock->pDataBlock, &idata);
-
-    if (IS_VAR_DATA_TYPE(idata.info.type)) {
-      pBlock->info.hasVarCol = true;
-    }
   }
 
   return pBlock;
@@ -4748,7 +4744,8 @@ static void appendOneRowToDataBlock(SSDataBlock* pBlock, STupleHandle* pTupleHan
   for (int32_t i = 0; i < pBlock->info.numOfCols; ++i) {
     SColumnInfoData* pColInfo = taosArrayGet(pBlock->pDataBlock, i);
 
-    bool isNull = tsortIsNullVal(pTupleHandle, i);
+    SColumnInfoData* pColInfoSrc = taosArrayGet(pTupleHandle->pBlock->pDataBlock, i);
+    bool isNull = colDataIsNull(pColInfoSrc, 0, pTupleHandle->rowIndex, NULL);
     if (isNull) {
       colDataAppend(pColInfo, pBlock->info.rows, NULL, true);
     } else {
diff --git a/source/libs/executor/src/tsort.c b/source/libs/executor/src/tsort.c
index a052cbe846d28599f0e4a775d17e547363c04ca4..b226106e018c993037b79e603e7eca7175ae6123 100644
--- a/source/libs/executor/src/tsort.c
+++ b/source/libs/executor/src/tsort.c
@@ -24,11 +24,6 @@
 #include "tutil.h"
 #include "tcompare.h"
 
-struct STupleHandle {
-  SSDataBlock* pBlock;
-  int32_t      rowIndex;
-};
-
 struct SSortHandle {
   int32_t           type;