diff --git a/source/libs/function/src/builtinsimpl.c b/source/libs/function/src/builtinsimpl.c
index 83227dea9e..aa0711f421 100644
--- a/source/libs/function/src/builtinsimpl.c
+++ b/source/libs/function/src/builtinsimpl.c
@@ -2449,13 +2449,21 @@ static int32_t doSaveCurrentVal(SqlFunctionCtx* pCtx, int32_t rowIndex, int64_t
   SFirstLastRes*       pInfo = GET_ROWCELL_INTERBUF(pResInfo);
 
   if (IS_VAR_DATA_TYPE(type)) {
-    pInfo->bytes = varDataTLen(pData);
+    if (type == TSDB_DATA_TYPE_JSON) {
+      pInfo->bytes = getJsonValueLen(pData);
+    } else {
+      pInfo->bytes = varDataTLen(pData);
+    }
   }
 
   (void)memcpy(pInfo->buf, pData, pInfo->bytes);
   if (pkData != NULL) {
     if (IS_VAR_DATA_TYPE(pInfo->pkType)) {
-      pInfo->pkBytes = varDataTLen(pkData);
+      if (pInfo->pkType == TSDB_DATA_TYPE_JSON) {
+        pInfo->pkBytes = getJsonValueLen(pkData);
+      } else {
+        pInfo->pkBytes = varDataTLen(pkData);
+      }
     }
     (void)memcpy(pInfo->buf + pInfo->bytes, pkData, pInfo->pkBytes);
     pInfo->pkData = pInfo->buf + pInfo->bytes;
@@ -2985,7 +2993,11 @@ static int32_t doSaveLastrow(SqlFunctionCtx* pCtx, char* pData, int32_t rowIndex
     pInfo->isNull = false;
 
     if (IS_VAR_DATA_TYPE(pInputCol->info.type)) {
-      pInfo->bytes = varDataTLen(pData);
+      if (pInputCol->info.type == TSDB_DATA_TYPE_JSON) {
+        pInfo->bytes = getJsonValueLen(pData);
+      } else {
+        pInfo->bytes = varDataTLen(pData);
+      }
     }
 
     (void)memcpy(pInfo->buf, pData, pInfo->bytes);
@@ -2994,7 +3006,11 @@ static int32_t doSaveLastrow(SqlFunctionCtx* pCtx, char* pData, int32_t rowIndex
   if (pCtx->hasPrimaryKey && !colDataIsNull_s(pkCol, rowIndex)) {
     char* pkData = colDataGetData(pkCol, rowIndex);
     if (IS_VAR_DATA_TYPE(pInfo->pkType)) {
-      pInfo->pkBytes = varDataTLen(pkData);
+      if (pInfo->pkType == TSDB_DATA_TYPE_JSON) {
+        pInfo->pkBytes = getJsonValueLen(pkData);
+      } else {
+        pInfo->pkBytes = varDataTLen(pkData);
+      }
     }
     (void)memcpy(pInfo->buf + pInfo->bytes, pkData, pInfo->pkBytes);
     pInfo->pkData = pInfo->buf + pInfo->bytes;
@@ -5872,7 +5888,11 @@ void modeFunctionCleanupExt(SqlFunctionCtx* pCtx) {
 
 static int32_t saveModeTupleData(SqlFunctionCtx* pCtx, char* data, SModeInfo *pInfo, STuplePos* pPos) {
   if (IS_VAR_DATA_TYPE(pInfo->colType)) {
-    (void)memcpy(pInfo->buf, data, varDataTLen(data));
+    if (pInfo->colType == TSDB_DATA_TYPE_JSON) {
+      (void)memcpy(pInfo->buf, data, getJsonValueLen(data));
+    } else {
+      (void)memcpy(pInfo->buf, data, varDataTLen(data));
+    }
   } else {
     (void)memcpy(pInfo->buf, data, pInfo->colBytes);
   }
@@ -5882,7 +5902,16 @@ static int32_t saveModeTupleData(SqlFunctionCtx* pCtx, char* data, SModeInfo *pI
 
 static int32_t doModeAdd(SModeInfo* pInfo, int32_t rowIndex, SqlFunctionCtx* pCtx, char* data) {
   int32_t code = TSDB_CODE_SUCCESS;
-  int32_t hashKeyBytes = IS_STR_DATA_TYPE(pInfo->colType) ? varDataTLen(data) : pInfo->colBytes;
+  int32_t hashKeyBytes;
+  if (IS_VAR_DATA_TYPE(pInfo->colType)) {
+    if (pInfo->colType == TSDB_DATA_TYPE_JSON) {
+      hashKeyBytes = getJsonValueLen(data);
+    } else {
+      hashKeyBytes = varDataTLen(data);
+    }
+  } else {
+    hashKeyBytes = pInfo->colBytes;
+  }
 
   SModeItem* pHashItem = (SModeItem *)taosHashGet(pInfo->pHash, data, hashKeyBytes);
   if (pHashItem == NULL) {
@@ -6654,14 +6683,32 @@ static void doSaveRateInfo(SRateInfo* pRateInfo, bool isFirst, int64_t ts, char*
     pRateInfo->firstValue = v;
     pRateInfo->firstKey = ts;
     if (pRateInfo->firstPk) {
-      int32_t pkBytes = IS_VAR_DATA_TYPE(pRateInfo->pkType) ? varDataTLen(pk) : pRateInfo->pkBytes;
+      int32_t pkBytes;
+      if (IS_VAR_DATA_TYPE(pRateInfo->pkType)) {
+        if (pRateInfo->pkType == TSDB_DATA_TYPE_JSON) {
+          pkBytes = getJsonValueLen(pk);
+        } else {
+          pkBytes = varDataTLen(pk);
+        }
+      } else {
+        pkBytes = pRateInfo->pkBytes;
+      }
       (void)memcpy(pRateInfo->firstPk, pk, pkBytes);
     }
   } else {
     pRateInfo->lastValue = v;
     pRateInfo->lastKey = ts;
     if (pRateInfo->lastPk) {
-      int32_t pkBytes = IS_VAR_DATA_TYPE(pRateInfo->pkType) ? varDataTLen(pk) : pRateInfo->pkBytes;
+      int32_t pkBytes;
+      if (IS_VAR_DATA_TYPE(pRateInfo->pkType)) {
+        if (pRateInfo->pkType == TSDB_DATA_TYPE_JSON) {
+          pkBytes = getJsonValueLen(pk);
+        } else {
+          pkBytes = varDataTLen(pk);
+        }
+      } else {
+        pkBytes = pRateInfo->pkBytes;
+      }
       (void)memcpy(pRateInfo->lastPk, pk, pkBytes);
     }
   }
diff --git a/tests/army/query/function/test_selection_function_with_json.py b/tests/army/query/function/test_selection_function_with_json.py
new file mode 100644
index 0000000000..e1f8090ae3
--- /dev/null
+++ b/tests/army/query/function/test_selection_function_with_json.py
@@ -0,0 +1,106 @@
+###################################################################
+#           Copyright (c) 2016 by TAOS Technologies, Inc.
+#                     All rights reserved.
+#
+#  This file is proprietary and confidential to TAOS Technologies.
+#  No part of this file may be reproduced, stored, transmitted,
+#  disclosed or used in any form or by any means other than as
+#  expressly provided by the written permission from Jianhui Tao
+#
+###################################################################
+
+# -*- coding: utf-8 -*-
+
+from frame import etool
+from frame.etool import *
+from frame.log import *
+from frame.cases import *
+from frame.sql import *
+from frame.caseBase import *
+from frame.common import *
+
+class TDTestCase(TBase):
+    updatecfgDict = {
+        "keepColumnName": "1",
+        "ttlChangeOnWrite": "1",
+        "querySmaOptimize": "1",
+        "slowLogScope": "none",
+        "queryBufferSize": 10240
+    }
+
+    def insert_data(self):
+        tdLog.info(f"insert data.")
+        tdSql.execute("drop database if exists ts_5763;")
+        tdSql.execute("create database ts_5763;")
+        tdSql.execute("use ts_5763;")
+        tdSql.execute("select database();")
+        tdSql.execute("CREATE STABLE metrics (ts TIMESTAMP, v DOUBLE) TAGS (labels JSON)")
+        tdSql.execute("""CREATE TABLE `metrics_0` USING `metrics` (`labels`) TAGS ('{"ident":"192.168.56.167"}');""")
+        tdSql.execute("""CREATE TABLE `metrics_1` USING `metrics` (`labels`) TAGS ('{"ident":"192.168.56.168"}');""")
+        tdSql.execute("""CREATE TABLE `metrics_2` USING `metrics` (`labels`) TAGS ('{"ident":"192.168.56.169"}');""")
+        tdSql.execute("""CREATE TABLE `metrics_3` USING `metrics` (`labels`) TAGS ('{"ident":"192.168.56.170"}');""")
+        tdSql.execute("""CREATE TABLE `metrics_5` USING `metrics` (`labels`) TAGS ('{"asset_name":"中国政务网"}');""")
+        tdSql.execute("""CREATE TABLE `metrics_6` USING `metrics` (`labels`) TAGS ('{"asset_name":"地大物博阿拉丁快解放啦上课交电费"}');""")
+        tdSql.execute("""CREATE TABLE `metrics_7` USING `metrics` (`labels`) TAGS ('{"asset_name":"no1241-上的六块腹肌阿斯利康的肌肤轮廓设计大方"}');""")
+        tdSql.execute("""CREATE TABLE `metrics_8` USING `metrics` (`labels`) TAGS ('{"asset_name":"no1241-上的六块腹肌阿斯利康的肌肤轮廓设计大方","ident":"192.168.0.1"}');""")
+        tdSql.execute("""CREATE TABLE `metrics_9` USING `metrics` (`labels`) TAGS ('{"asset_name":"no1241-上的六块腹肌阿斯利康的肌肤轮廓设计大方","ident":"192.168.0.1"}');""")
+        tdSql.execute("""CREATE TABLE `metrics_10` USING `metrics` (`labels`) TAGS ('{"asset_name":"上的咖啡机no1241-上的六块腹肌阿斯利康的肌肤轮廓设计大方","ident":"192.168.0.1"}');""")
+
+        tdSql.execute("insert into metrics_0 values ('2024-12-12 16:34:39.326',1)")
+        tdSql.execute("insert into metrics_0 values ('2024-12-12 16:34:40.891',2)")
+        tdSql.execute("insert into metrics_0 values ('2024-12-12 16:34:41.986',3)")
+        tdSql.execute("insert into metrics_0 values ('2024-12-12 16:34:42.992',4)")
+        tdSql.execute("insert into metrics_0 values ('2024-12-12 16:34:46.927',5)")
+        tdSql.execute("insert into metrics_0 values ('2024-12-12 16:34:48.473',6)")
+        tdSql.execute("insert into metrics_1 select * from metrics_0")
+        tdSql.execute("insert into metrics_2 select * from metrics_0")
+        tdSql.execute("insert into metrics_3 select * from metrics_0")
+        tdSql.execute("insert into metrics_5 select * from metrics_0")
+        tdSql.execute("insert into metrics_6 select * from metrics_0")
+        tdSql.execute("insert into metrics_7 select * from metrics_0")
+        tdSql.execute("insert into metrics_8 values ('2024-12-12 19:05:36.459',1)")
+        tdSql.execute("insert into metrics_8 values ('2024-12-12 19:05:37.388',1)")
+        tdSql.execute("insert into metrics_8 values ('2024-12-12 19:05:37.622',1)")
+        tdSql.execute("insert into metrics_8 values ('2024-12-12 19:05:37.852',1)")
+        tdSql.execute("insert into metrics_8 values ('2024-12-12 19:05:38.081',1)")
+        tdSql.execute("insert into metrics_8 values ('2024-12-12 19:05:38.307',1)")
+        tdSql.execute("insert into metrics_8 values ('2024-12-12 19:05:38.535',1)")
+        tdSql.execute("insert into metrics_8 values ('2024-12-12 19:05:38.792',1)")
+        tdSql.execute("insert into metrics_8 values ('2024-12-12 19:05:39.035',1)")
+        tdSql.execute("insert into metrics_8 values ('2024-12-12 19:05:39.240',1)")
+        tdSql.execute("insert into metrics_9 values ('2024-12-12 19:05:29.270',1)")
+        tdSql.execute("insert into metrics_9 values ('2024-12-12 19:05:30.508',1)")
+        tdSql.execute("insert into metrics_9 values ('2024-12-12 19:05:31.035',1)")
+        tdSql.execute("insert into metrics_9 values ('2024-12-12 19:05:31.523',1)")
+        tdSql.execute("insert into metrics_9 values ('2024-12-12 19:05:31.760',1)")
+        tdSql.execute("insert into metrics_9 values ('2024-12-12 19:05:32.001',1)")
+        tdSql.execute("insert into metrics_9 values ('2024-12-12 19:05:32.228',1)")
+        tdSql.execute("insert into metrics_9 values ('2024-12-12 19:05:32.453',1)")
+        tdSql.execute("insert into metrics_9 values ('2024-12-12 19:05:32.690',1)")
+        tdSql.execute("insert into metrics_9 values ('2024-12-12 19:05:32.906',1)")
+        tdSql.execute("insert into metrics_10 values ('2024-12-12 19:06:14.538',1)")
+        tdSql.execute("insert into metrics_10 values ('2024-12-12 19:06:15.114',1)")
+        tdSql.execute("insert into metrics_10 values ('2024-12-12 19:06:15.613',1)")
+        tdSql.execute("insert into metrics_10 values ('2024-12-12 19:06:15.853',1)")
+        tdSql.execute("insert into metrics_10 values ('2024-12-12 19:06:16.054',1)")
+        tdSql.execute("insert into metrics_10 values ('2024-12-12 19:06:16.295',1)")
+        tdSql.execute("insert into metrics_10 values ('2024-12-12 19:06:16.514',1)")
+        tdSql.execute("insert into metrics_10 values ('2024-12-12 19:06:16.731',1)")
+        tdSql.execute("insert into metrics_10 values ('2024-12-12 19:06:16.958',1)")
+        tdSql.execute("insert into metrics_10 values ('2024-12-12 19:06:17.176',1)")
+
+        for i in range(1, 10):
+            tdSql.query("select _wstart,first(v)-last(v), first(labels->'asset_name'),first(labels->'ident'),mode(labels->'asset_name'),mode(labels->'ident'),last(labels->'asset_name'),last(labels->'ident') from ts_5763.metrics interval(1s)")
+            tdSql.checkRows(18)
+
+    def run(self):
+        tdLog.debug(f"start to excute {__file__}")
+
+        self.insert_data()
+
+
+        tdLog.success(f"{__file__} successfully executed")
+
+
+tdCases.addLinux(__file__, TDTestCase())
+tdCases.addWindows(__file__, TDTestCase())
diff --git a/tests/parallel_test/cases.task b/tests/parallel_test/cases.task
index 879d93ab3a..e82fd5a85d 100644
--- a/tests/parallel_test/cases.task
+++ b/tests/parallel_test/cases.task
@@ -15,6 +15,7 @@
 ,,y,army,./pytest.sh python3 ./test.py -f cluster/snapshot.py -N 3 -L 3 -D 2
 ,,y,army,./pytest.sh python3 ./test.py -f query/function/test_func_elapsed.py
 ,,y,army,./pytest.sh python3 ./test.py -f query/function/test_function.py
+,,y,army,./pytest.sh python3 ./test.py -f query/function/test_selection_function_with_json.py
 ,,y,army,./pytest.sh python3 ./test.py -f query/function/test_percentile.py
 ,,y,army,./pytest.sh python3 ./test.py -f query/function/test_resinfo.py
 ,,y,army,./pytest.sh python3 ./test.py -f query/function/test_interp.py