diff --git a/source/libs/function/src/builtins.c b/source/libs/function/src/builtins.c
index e4172b97fcf521c7be099ca760afec533a4dc760..c1cdcbcb0c2170e3475d62b5a98d4be945fa562b 100644
--- a/source/libs/function/src/builtins.c
+++ b/source/libs/function/src/builtins.c
@@ -576,29 +576,6 @@ int32_t stubCheckAndGetResultType(SFunctionNode* pFunc) {
       }
       pFunc->node.resType = (SDataType) { .bytes = paraBytes, .type = paraType };
       break;
-      //int32_t paraTypeFirst, totalBytes = 0, sepBytes = 0;
-      //int32_t firstParamIndex = 0;
-      //if (pFunc->funcType == FUNCTION_TYPE_CONCAT_WS) {
-      //  firstParamIndex = 1;
-      //  SColumnNode* pSep = nodesListGetNode(pFunc->pParameterList, 0);
-      //  sepBytes = pSep->node.resType.type;
-      //}
-      //for (int32_t i = firstParamIndex; i < pFunc->pParameterList->length; ++i) {
-      //  SColumnNode* pParam = nodesListGetNode(pFunc->pParameterList, i);
-      //  int32_t paraType = pParam->node.resType.type;
-      //  if (i == firstParamIndex) {
-      //    paraTypeFirst = paraType;
-      //  }
-      //  if (paraType != paraTypeFirst) {
-      //    return TSDB_CODE_FAILED;
-      //  }
-      //  //TODO: for constants also needs numOfRows
-      //  totalBytes += pParam->node.resType.bytes;
-      //}
-      ////TODO: need to get numOfRows to decide how much space separator needed. Currently set to 100.
-      //totalBytes += sepBytes * (pFunc->pParameterList->length - 2) * 100;
-      //pFunc->node.resType = (SDataType) { .bytes = totalBytes, .type = paraTypeFirst };
-      //break;
     }
     case FUNCTION_TYPE_LOWER:
     case FUNCTION_TYPE_UPPER:
diff --git a/source/libs/scalar/src/sclfunc.c b/source/libs/scalar/src/sclfunc.c
index 0335b7c4f57ac2b0b0fc4699df47c1cd1efa08bf..1a6abb7100a304026628ca5aad6c194820744064 100644
--- a/source/libs/scalar/src/sclfunc.c
+++ b/source/libs/scalar/src/sclfunc.c
@@ -609,7 +609,7 @@ int32_t substrFunction(SScalarParam *pInput, int32_t inputNum, SScalarParam *pOu
   char *input  = pInputData->pData;
   char *output = NULL;
 
-  int32_t outputLen = pInputData->varmeta.length;
+  int32_t outputLen = pInputData->varmeta.length * pInput->numOfRows;
   char *outputBuf = taosMemoryCalloc(outputLen, 1);
   output = outputBuf;
 
@@ -630,12 +630,12 @@ int32_t substrFunction(SScalarParam *pInput, int32_t inputNum, SScalarParam *pOu
       startPosBytes = MAX(startPosBytes, 0);
     }
 
-    subLen = MIN(subLen, len - startPosBytes);
-    if (subLen > 0) {
-      memcpy(varDataVal(output), varDataVal(input) + startPosBytes, subLen);
+    int32_t resLen = MIN(subLen, len - startPosBytes);
+    if (resLen > 0) {
+      memcpy(varDataVal(output), varDataVal(input) + startPosBytes, resLen);
     }
 
-    varDataSetLen(output, subLen);
+    varDataSetLen(output, resLen);
     colDataAppend(pOutputData, i , output, false);
     input += varDataTLen(input);
     output += varDataTLen(output);