diff --git a/source/libs/function/src/builtins.c b/source/libs/function/src/builtins.c
index a52e39bd4f58343c0166145a9c444e7c366c0101..70087ee46bf3b2f49a8876372c1df75c8cdb582a 100644
--- a/source/libs/function/src/builtins.c
+++ b/source/libs/function/src/builtins.c
@@ -355,7 +355,7 @@ static int32_t translateToIso8601(SFunctionNode* pFunc, char* pErrBuf, int32_t l
     return invaildFuncParaTypeErrMsg(pErrBuf, len, pFunc->functionName);
   }
 
-  pFunc->node.resType = (SDataType) { .bytes = 24, .type = TSDB_DATA_TYPE_BINARY};
+  pFunc->node.resType = (SDataType) { .bytes = 64, .type = TSDB_DATA_TYPE_BINARY};
   return TSDB_CODE_SUCCESS;
 }
 
diff --git a/source/libs/scalar/src/scalar.c b/source/libs/scalar/src/scalar.c
index 820a4894b5ed756bcacfe030211b24b35e86b11e..d6c0989f19d66a3fb809080005ce044f7ce10488 100644
--- a/source/libs/scalar/src/scalar.c
+++ b/source/libs/scalar/src/scalar.c
@@ -489,7 +489,7 @@ EDealRes sclRewriteFunction(SNode** pNode, SScalarCtx *ctx) {
   if (fmIsUserDefinedFunc(node->funcId)) {
     return DEAL_RES_CONTINUE;
   }
-  
+
   FOREACH(tnode, node->pParameterList) {
     if (!SCL_IS_CONST_NODE(tnode)) {
       return DEAL_RES_CONTINUE;
@@ -517,8 +517,10 @@ EDealRes sclRewriteFunction(SNode** pNode, SScalarCtx *ctx) {
     res->node.resType = node->node.resType;
     int32_t type = output.columnData->info.type;
     if (IS_VAR_DATA_TYPE(type)) {
-      res->datum.p = output.columnData->pData;
-      output.columnData->pData = NULL;
+      size_t tLen = varDataLen(output.columnData->pData);
+      ASSERT(tLen <= res->node.resType.bytes);
+      res->datum.p = taosMemoryCalloc(res->node.resType.bytes + VARSTR_HEADER_SIZE + 1, 1);
+      memcpy(res->datum.p, output.columnData->pData, tLen);
     } else {
       memcpy(nodesGetValueFromNode(res), output.columnData->pData, tDataTypes[type].bytes);
     }