diff --git a/source/libs/executor/src/executil.c b/source/libs/executor/src/executil.c
index 38304bcc76ed03fb80af23aa9b29be1b1c8a89e1..f5b693168001f86ee3a0e685c72b40044f4eb70f 100644
--- a/source/libs/executor/src/executil.c
+++ b/source/libs/executor/src/executil.c
@@ -1209,6 +1209,17 @@ void createExprFromTargetNode(SExprInfo* pExp, STargetNode* pTargetNode) {
     pExp->base.pParam = taosMemoryCalloc(1, sizeof(SFunctParam));
     pExp->base.numOfParams = 1;
 
+    SDataType* pType = &pNode->node.resType;
+    pExp->base.resSchema = createResSchema(pType->type, pType->bytes, pTargetNode->slotId, pType->scale,
+                                           pType->precision, pNode->node.aliasName);
+    pExp->pExpr->_optrRoot.pRootNode = pTargetNode->pExpr;
+  } else if (type == QUERY_NODE_CASE_WHEN) {
+    pExp->pExpr->nodeType = QUERY_NODE_OPERATOR;
+    SCaseWhenNode* pNode = (SCaseWhenNode*)pTargetNode->pExpr;
+  
+    pExp->base.pParam = taosMemoryCalloc(1, sizeof(SFunctParam));
+    pExp->base.numOfParams = 1;
+  
     SDataType* pType = &pNode->node.resType;
     pExp->base.resSchema = createResSchema(pType->type, pType->bytes, pTargetNode->slotId, pType->scale,
                                            pType->precision, pNode->node.aliasName);
diff --git a/source/libs/scalar/inc/sclInt.h b/source/libs/scalar/inc/sclInt.h
index 15e9026ddbc2eea8ad4e066519dd4bbea9767b7e..e974d50c56cd014119a828ebe5167689e0906755 100644
--- a/source/libs/scalar/inc/sclInt.h
+++ b/source/libs/scalar/inc/sclInt.h
@@ -69,6 +69,9 @@ int32_t sclConvertToTsValueNode(int8_t precision, SValueNode* valueNode);
 #define GET_PARAM_PRECISON(_c)  ((_c)->columnData->info.precision)
 
 void sclFreeParam(SScalarParam *param);
+void doVectorCompare(SScalarParam* pLeft, SScalarParam* pRight, SScalarParam *pOut, int32_t startIndex, int32_t numOfRows, 
+                     int32_t _ord, int32_t optr);
+void vectorCompare(SScalarParam* pLeft, SScalarParam* pRight, SScalarParam *pOut, int32_t _ord, int32_t optr);
 
 #ifdef __cplusplus
 }
diff --git a/source/libs/scalar/src/scalar.c b/source/libs/scalar/src/scalar.c
index 8c387bf6a95d8ee09d3a9531481964c5a809db67..b0063e8c9787ff95ff0d1c8662b519eed08990e1 100644
--- a/source/libs/scalar/src/scalar.c
+++ b/source/libs/scalar/src/scalar.c
@@ -76,6 +76,28 @@ int32_t doConvertDataType(SValueNode* pValueNode, SScalarParam* out, int32_t* ov
   return code;
 }
 
+int32_t sclExtendResRows(SScalarParam *pDst, SScalarParam *pSrc, SArray *pBlockList) {
+  SSDataBlock* pb = taosArrayGetP(pBlockList, 0);
+  SScalarParam *pLeft = taosMemoryCalloc(1, sizeof(SScalarParam));
+  if (NULL == pLeft) {
+    sclError("calloc %d failed", (int32_t)sizeof(SScalarParam));
+    SCL_ERR_RET(TSDB_CODE_QRY_OUT_OF_MEMORY);
+  }
+
+  pLeft->numOfRows = pb->info.rows;
+
+  if (pDst->numOfRows < pb->info.rows) {
+    colInfoDataEnsureCapacity(pDst->columnData, pb->info.rows);
+  }
+  
+  _bin_scalar_fn_t OperatorFn = getBinScalarOperatorFn(OP_TYPE_ASSIGN);
+  OperatorFn(pLeft, pSrc, pDst, TSDB_ORDER_ASC);
+
+  taosMemoryFree(pLeft);
+
+  return TSDB_CODE_SUCCESS;
+}
+
 int32_t scalarGenerateSetFromList(void **data, void *pNode, uint32_t type) {
   SHashObj *pObj = taosHashInit(256, taosGetDefaultHashFunction(type), true, false);
   if (NULL == pObj) {
@@ -549,11 +571,12 @@ int32_t sclGetNodeRes(SNode* node, SScalarCtx *ctx, SScalarParam **res) {
   return TSDB_CODE_SUCCESS;
 }
 
-int32_t sclWalkCaseWhenList(SScalarCtx *ctx, SNodeList* pList, struct SListCell* pCell, SScalarParam *pCase, SScalarParam *pElse, SScalarParam *pComp, SScalarParam *output, int32_t rowIdx) {
+int32_t sclWalkCaseWhenList(SScalarCtx *ctx, SNodeList* pList, struct SListCell* pCell, SScalarParam *pCase, SScalarParam *pElse, SScalarParam *pComp, SScalarParam *output, int32_t rowIdx, int32_t totalRows, bool *complete) {
   SNode *node = NULL;
   SWhenThenNode* pWhenThen = NULL;
   SScalarParam *pWhen = NULL;
   SScalarParam *pThen = NULL;
+  int32_t code = 0;
 
   for (SListCell* cell = pCell; (NULL != cell ? (node = cell->pNode, true) : (node = NULL, false)); cell = cell->pNext) {
     pWhenThen = (SWhenThenNode*)node;
@@ -563,26 +586,46 @@ int32_t sclWalkCaseWhenList(SScalarCtx *ctx, SNodeList* pList, struct SListCell*
     
     doVectorCompare(pCase, pWhen, pComp, rowIdx, 1, TSDB_ORDER_ASC, OP_TYPE_EQUAL);
     
-    bool *equal = colDataGetData(pComp->columnData, rowIdx);
+    bool *equal = (bool*)colDataGetData(pComp->columnData, rowIdx);
     if (*equal) {
-      colDataAppend(output->columnData, rowIdx, colDataGetData(pThen, (pThen->numOfRows > 1 ? rowIdx : 0)), colDataIsNull_s(pThen, (pThen->numOfRows > 1 ? rowIdx : 0)));
+      colDataAppend(output->columnData, rowIdx, colDataGetData(pThen->columnData, (pThen->numOfRows > 1 ? rowIdx : 0)), colDataIsNull_s(pThen->columnData, (pThen->numOfRows > 1 ? rowIdx : 0)));
+
+      if (0 == rowIdx && 1 == pCase->numOfRows && 1 == pWhen->numOfRows && 1 == pThen->numOfRows && totalRows > 1) {
+        SCL_ERR_JRET(sclExtendResRows(output, output, ctx->pBlockList));
+        *complete = true;
+      }
       
-      return TSDB_CODE_SUCCESS;
+      goto _return;
     }
   }
 
   if (pElse) {
-    colDataAppend(output->columnData, rowIdx, colDataGetData(pElse, (pElse->numOfRows > 1 ? rowIdx : 0)), colDataIsNull_s(pElse, (pElse->numOfRows > 1 ? rowIdx : 0)));
-    
-    return TSDB_CODE_SUCCESS;
+    colDataAppend(output->columnData, rowIdx, colDataGetData(pElse->columnData, (pElse->numOfRows > 1 ? rowIdx : 0)), colDataIsNull_s(pElse->columnData, (pElse->numOfRows > 1 ? rowIdx : 0)));
+
+    if (0 == rowIdx && 1 == pCase->numOfRows && 1 == pElse->numOfRows && totalRows > 1) {
+      SCL_ERR_JRET(sclExtendResRows(output, output, ctx->pBlockList));
+      *complete = true;
+    }
+      
+    goto _return;
   }
 
   colDataAppend(output->columnData, rowIdx, NULL, true);
 
-  return TSDB_CODE_SUCCESS;
+  if (0 == rowIdx && totalRows > 1) {
+    SCL_ERR_JRET(sclExtendResRows(output, output, ctx->pBlockList));
+    *complete = true;
+  }
+
+_return:
+  
+  sclFreeParam(pWhen);
+  sclFreeParam(pThen);
+
+  SCL_RET(code);
 }
 
-int32_t sclWalkWhenList(SScalarCtx *ctx, SNodeList* pList, struct SListCell* pCell, SScalarParam *pElse, SScalarParam *output, int32_t rowIdx) {
+int32_t sclWalkWhenList(SScalarCtx *ctx, SNodeList* pList, struct SListCell* pCell, SScalarParam *pElse, SScalarParam *output, int32_t rowIdx, int32_t totalRows, bool *complete) {
   SNode *node = NULL;
   SWhenThenNode* pWhenThen = NULL;
   SScalarParam *pWhen = NULL;
@@ -597,13 +640,14 @@ int32_t sclWalkWhenList(SScalarCtx *ctx, SNodeList* pList, struct SListCell* pCe
     SCL_ERR_JRET(sclGetNodeRes(pWhenThen->pWhen, ctx, &pWhen));
     SCL_ERR_JRET(sclGetNodeRes(pWhenThen->pThen, ctx, &pThen));
 
-    bool *whenValue = colDataGetData(pWhen->columnData, (pWhen->numOfRows > 1 ? rowIdx : 0));
+    bool *whenValue = (bool*)colDataGetData(pWhen->columnData, (pWhen->numOfRows > 1 ? rowIdx : 0));
     
     if (*whenValue) {
-      colDataAppend(output->columnData, rowIdx, colDataGetData(pThen, (pThen->numOfRows > 1 ? rowIdx : 0)), colDataIsNull_s(pThen, (pThen->numOfRows > 1 ? rowIdx : 0)));
+      colDataAppend(output->columnData, rowIdx, colDataGetData(pThen->columnData, (pThen->numOfRows > 1 ? rowIdx : 0)), colDataIsNull_s(pThen->columnData, (pThen->numOfRows > 1 ? rowIdx : 0)));
 
-      if (0 == rowIdx && 1 == pWhen->numOfRows) {
+      if (0 == rowIdx && 1 == pWhen->numOfRows && 1 == pThen->numOfRows && totalRows > 1) {
         SCL_ERR_JRET(sclExtendResRows(output, output, ctx->pBlockList));
+        *complete = true;
       }
       
       goto _return;
@@ -614,10 +658,11 @@ int32_t sclWalkWhenList(SScalarCtx *ctx, SNodeList* pList, struct SListCell* pCe
   }
 
   if (pElse) {
-    colDataAppend(output->columnData, rowIdx, colDataGetData(pElse, (pElse->numOfRows > 1 ? rowIdx : 0)), colDataIsNull_s(pElse, (pElse->numOfRows > 1 ? rowIdx : 0)));
+    colDataAppend(output->columnData, rowIdx, colDataGetData(pElse->columnData, (pElse->numOfRows > 1 ? rowIdx : 0)), colDataIsNull_s(pElse->columnData, (pElse->numOfRows > 1 ? rowIdx : 0)));
 
-    if (0 == rowIdx && 1 == pElse->numOfRows) {
+    if (0 == rowIdx && 1 == pElse->numOfRows && totalRows > 1) {
       SCL_ERR_JRET(sclExtendResRows(output, output, ctx->pBlockList));
+      *complete = true;
     }
       
     goto _return;
@@ -625,8 +670,9 @@ int32_t sclWalkWhenList(SScalarCtx *ctx, SNodeList* pList, struct SListCell* pCe
 
   colDataAppend(output->columnData, rowIdx, NULL, true);
 
-  if (0 == rowIdx) {
+  if (0 == rowIdx && totalRows > 1) {
     SCL_ERR_JRET(sclExtendResRows(output, output, ctx->pBlockList));
+    *complete = true;
   }
 
 _return:
@@ -637,8 +683,6 @@ _return:
   SCL_RET(code);
 }
 
-
-
 int32_t sclExecFunction(SFunctionNode *node, SScalarCtx *ctx, SScalarParam *output) {
   SScalarParam *params = NULL;
   int32_t rowNum = 0;
@@ -801,8 +845,9 @@ int32_t sclExecCaseWhen(SCaseWhenNode *node, SScalarCtx *ctx, SScalarParam *outp
   SScalarParam *pElse = NULL;
   SScalarParam *pWhen = NULL;
   SScalarParam *pThen = NULL;
-  SScalarParam *pComp = NULL;
+  SScalarParam  comp = {0};
   int32_t rowNum = 1;
+  bool complete = false;
 
   if (NULL == node->pWhenThenList || node->pWhenThenList->length <= 0) {
     sclError("invalid whenThen list");
@@ -812,6 +857,7 @@ int32_t sclExecCaseWhen(SCaseWhenNode *node, SScalarCtx *ctx, SScalarParam *outp
   if (ctx->pBlockList) {
     SSDataBlock* pb = taosArrayGetP(ctx->pBlockList, 0);
     rowNum = pb->info.rows;
+    output->numOfRows = pb->info.rows;
   }
 
   SCL_ERR_JRET(sclCreateColumnInfoData(&node->node.resType, rowNum, output));
@@ -823,7 +869,7 @@ int32_t sclExecCaseWhen(SCaseWhenNode *node, SScalarCtx *ctx, SScalarParam *outp
   compType.type = TSDB_DATA_TYPE_BOOL;
   compType.bytes = tDataTypes[compType.type].bytes;
   
-  SCL_ERR_JRET(sclCreateColumnInfoData(&compType, rowNum, pComp));
+  SCL_ERR_JRET(sclCreateColumnInfoData(&compType, rowNum, &comp));
 
   SNode* tnode = NULL;
   SWhenThenNode* pWhenThen = (SWhenThenNode*)node->pWhenThenList->pHead->pNode;
@@ -832,31 +878,44 @@ int32_t sclExecCaseWhen(SCaseWhenNode *node, SScalarCtx *ctx, SScalarParam *outp
   SCL_ERR_JRET(sclGetNodeRes(pWhenThen->pThen, ctx, &pThen));
 
   if (pCase) {
-    vectorCompare(pCase, pWhen, pComp, TSDB_ORDER_ASC, OP_TYPE_EQUAL);
+    vectorCompare(pCase, pWhen, &comp, TSDB_ORDER_ASC, OP_TYPE_EQUAL);
     
     for (int32_t i = 0; i < rowNum; ++i) {
-      bool *equal = colDataGetData(pComp->columnData, i);
+      bool *equal = (bool*)colDataGetData(comp.columnData, (comp.numOfRows > 1 ? i : 0));
       if (*equal) {
-        colDataAppend(output->columnData, i, colDataGetData(pThen, (pThen->numOfRows > 1 ? i : 0)), colDataIsNull_s(pThen, (pThen->numOfRows > 1 ? i : 0)));
+        colDataAppend(output->columnData, i, colDataGetData(pThen->columnData, (pThen->numOfRows > 1 ? i : 0)), colDataIsNull_s(pThen->columnData, (pThen->numOfRows > 1 ? i : 0)));
+        if (0 == i && 1 == pWhen->numOfRows && 1 == pThen->numOfRows && rowNum > 1) {
+          SCL_ERR_JRET(sclExtendResRows(output, output, ctx->pBlockList));
+          break;
+        }
       } else {
-        SCL_ERR_JRET(sclWalkCaseWhenList(ctx, node->pWhenThenList, node->pWhenThenList->pHead->pNext, pCase, pElse, pComp, output, i));
+        SCL_ERR_JRET(sclWalkCaseWhenList(ctx, node->pWhenThenList, node->pWhenThenList->pHead->pNext, pCase, pElse, &comp, output, i, rowNum, &complete));
+        if (complete) {
+          break;
+        }
       }
     }
   } else {
     for (int32_t i = 0; i < rowNum; ++i) {
-      bool *equal = colDataGetData(pWhen->columnData, (pThen->numOfRows > 1 ? i : 0));
-      if (*equal) {
-        colDataAppend(output->columnData, i, colDataGetData(pThen, (pThen->numOfRows > 1 ? i : 0)), colDataIsNull_s(pThen, (pThen->numOfRows > 1 ? i : 0)));
-        SCL_ERR_JRET(sclExtendResRows(output, output, ctx->pBlockList));
+      bool *whenValue = (bool*)colDataGetData(pWhen->columnData, (pWhen->numOfRows > 1 ? i : 0));
+      if (*whenValue) {
+        colDataAppend(output->columnData, i, colDataGetData(pThen->columnData, (pThen->numOfRows > 1 ? i : 0)), colDataIsNull_s(pThen->columnData, (pThen->numOfRows > 1 ? i : 0)));
+        if (0 == i && 1 == pWhen->numOfRows && 1 == pThen->numOfRows && rowNum > 1) {
+          SCL_ERR_JRET(sclExtendResRows(output, output, ctx->pBlockList));
+          break;
+        }
       } else {
-        SCL_ERR_JRET(sclWalkWhenList(ctx, node->pWhenThenList, node->pWhenThenList->pHead->pNext, pElse, output, i));
+        SCL_ERR_JRET(sclWalkWhenList(ctx, node->pWhenThenList, node->pWhenThenList->pHead->pNext, pElse, output, i, rowNum, &complete));
+        if (complete) {
+          break;
+        }
       }
     }
   }
 
   sclFreeParam(pCase);
   sclFreeParam(pElse);
-  sclFreeParam(pComp);
+  sclFreeParam(&comp);
   sclFreeParam(pWhen);
   sclFreeParam(pThen);
 
@@ -866,7 +925,7 @@ _return:
 
   sclFreeParam(pCase);
   sclFreeParam(pElse);
-  sclFreeParam(pComp);
+  sclFreeParam(&comp);
   sclFreeParam(pWhen);
   sclFreeParam(pThen);
   sclFreeParam(output);
@@ -1332,7 +1391,9 @@ EDealRes sclWalkCaseWhen(SNode* pNode, SScalarCtx *ctx) {
 
 
 EDealRes sclCalcWalker(SNode* pNode, void* pContext) {
-  if (QUERY_NODE_VALUE == nodeType(pNode) || QUERY_NODE_NODE_LIST == nodeType(pNode) || QUERY_NODE_COLUMN == nodeType(pNode)|| QUERY_NODE_LEFT_VALUE == nodeType(pNode)) {
+  if (QUERY_NODE_VALUE == nodeType(pNode) || QUERY_NODE_NODE_LIST == nodeType(pNode) 
+   || QUERY_NODE_COLUMN == nodeType(pNode) || QUERY_NODE_LEFT_VALUE == nodeType(pNode)
+   || QUERY_NODE_WHEN_THEN == nodeType(pNode)) {
     return DEAL_RES_CONTINUE;
   }
 
@@ -1362,25 +1423,6 @@ EDealRes sclCalcWalker(SNode* pNode, void* pContext) {
   return DEAL_RES_ERROR;
 }
 
-int32_t sclExtendResRows(SScalarParam *pDst, SScalarParam *pSrc, SArray *pBlockList) {
-  SSDataBlock* pb = taosArrayGetP(pBlockList, 0);
-  SScalarParam *pLeft = taosMemoryCalloc(1, sizeof(SScalarParam));
-  if (NULL == pLeft) {
-    sclError("calloc %d failed", (int32_t)sizeof(SScalarParam));
-    SCL_ERR_RET(TSDB_CODE_QRY_OUT_OF_MEMORY);
-  }
-
-  pLeft->numOfRows = pb->info.rows;
-  colInfoDataEnsureCapacity(pDst->columnData, pb->info.rows);
-
-  _bin_scalar_fn_t OperatorFn = getBinScalarOperatorFn(OP_TYPE_ASSIGN);
-  OperatorFn(pLeft, pSrc, pDst, TSDB_ORDER_ASC);
-
-  taosMemoryFree(pLeft);
-
-  return TSDB_CODE_SUCCESS;
-}
-
 int32_t sclCalcConstants(SNode *pNode, bool dual, SNode **pRes) {
   if (NULL == pNode) {
     SCL_ERR_RET(TSDB_CODE_QRY_INVALID_INPUT);
diff --git a/source/libs/scalar/src/sclvector.c b/source/libs/scalar/src/sclvector.c
index 41725a1cb7bc309cf65e2e4cb633d9a61cedac59..fac0753cd113e9533756792a1af7bb6c4f3ec51b 100644
--- a/source/libs/scalar/src/sclvector.c
+++ b/source/libs/scalar/src/sclvector.c
@@ -1715,10 +1715,9 @@ void doVectorCompare(SScalarParam* pLeft, SScalarParam* pRight, SScalarParam *pO
     fp = filterGetCompFuncEx(lType, rType, optr);
   }
 
-  pOut->numOfRows = TMAX(pLeft->numOfRows, pRight->numOfRows);
-
   if (startIndex < 0) {
     i = ((_ord) == TSDB_ORDER_ASC) ? 0 : TMAX(pLeft->numOfRows, pRight->numOfRows) - 1;
+    pOut->numOfRows = TMAX(pLeft->numOfRows, pRight->numOfRows);
     compRows = pOut->numOfRows;
   } else {
     compRows = startIndex + numOfRows;