diff --git a/source/libs/function/src/builtinsimpl.c b/source/libs/function/src/builtinsimpl.c
index 2a1b1783534c59ba537ff2aa49e55197923ccb86..1501bb6d6755cde73a49e21266701f80ee554a80 100644
--- a/source/libs/function/src/builtinsimpl.c
+++ b/source/libs/function/src/builtinsimpl.c
@@ -181,6 +181,7 @@ typedef enum { UNKNOWN_BIN = 0, USER_INPUT_BIN, LINEAR_BIN, LOG_BIN } EHistoBinT
 
 typedef struct SHLLFuncInfo {
   uint64_t result;
+  uint64_t totalCount;
   uint8_t  buckets[HLL_BUCKETS];
 } SHLLInfo;
 
@@ -551,7 +552,7 @@ int32_t countFunction(SqlFunctionCtx* pCtx) {
   if (tsCountAlwaysReturnValue) {
     pResInfo->numOfRes = 1;
   } else {
-    SET_VAL(pResInfo, 1, 1);
+    SET_VAL(pResInfo, *((int64_t*)buf), 1);
   }
 
   return TSDB_CODE_SUCCESS;
@@ -4605,7 +4606,14 @@ int32_t hllFunction(SqlFunctionCtx* pCtx) {
     }
   }
 
-  SET_VAL(GET_RES_INFO(pCtx), numOfElems, 1);
+  pInfo->totalCount += numOfElems;
+
+  if (pInfo->totalCount == 0 && !tsCountAlwaysReturnValue) {
+    SET_VAL(GET_RES_INFO(pCtx), 0, 1);
+  } else {
+    SET_VAL(GET_RES_INFO(pCtx), 1, 1);
+  }
+
   return TSDB_CODE_SUCCESS;
 }
 
@@ -4615,6 +4623,7 @@ static void hllTransferInfo(SHLLInfo* pInput, SHLLInfo* pOutput) {
       pOutput->buckets[k] = pInput->buckets[k];
     }
   }
+  pOutput->totalCount += pInput->totalCount;
 }
 
 int32_t hllFunctionMerge(SqlFunctionCtx* pCtx) {
@@ -4632,7 +4641,12 @@ int32_t hllFunctionMerge(SqlFunctionCtx* pCtx) {
     hllTransferInfo(pInputInfo, pInfo);
   }
 
-  SET_VAL(GET_RES_INFO(pCtx), 1, 1);
+  if (pInfo->totalCount == 0 && !tsCountAlwaysReturnValue) {
+    SET_VAL(GET_RES_INFO(pCtx), 0, 1);
+  } else {
+    SET_VAL(GET_RES_INFO(pCtx), 1, 1);
+  }
+
   return TSDB_CODE_SUCCESS;
 }
 
diff --git a/source/libs/function/src/functionMgt.c b/source/libs/function/src/functionMgt.c
index 0de914271c4af17c7d865f4d88453ee456b1ee4a..6ab91a4483eeaf0dabf5968c6f0cd424cb80fb96 100644
--- a/source/libs/function/src/functionMgt.c
+++ b/source/libs/function/src/functionMgt.c
@@ -241,7 +241,11 @@ bool fmIsNotNullOutputFunc(int32_t funcId) {
          FUNCTION_TYPE_LAST_MERGE == funcMgtBuiltins[funcId].type ||
          FUNCTION_TYPE_FIRST == funcMgtBuiltins[funcId].type ||
          FUNCTION_TYPE_FIRST_PARTIAL == funcMgtBuiltins[funcId].type ||
-         FUNCTION_TYPE_FIRST_MERGE == funcMgtBuiltins[funcId].type;
+         FUNCTION_TYPE_FIRST_MERGE == funcMgtBuiltins[funcId].type ||
+         FUNCTION_TYPE_COUNT == funcMgtBuiltins[funcId].type ||
+         FUNCTION_TYPE_HYPERLOGLOG == funcMgtBuiltins[funcId].type ||
+         FUNCTION_TYPE_HYPERLOGLOG_PARTIAL == funcMgtBuiltins[funcId].type ||
+         FUNCTION_TYPE_HYPERLOGLOG_MERGE == funcMgtBuiltins[funcId].type;
 }
 
 bool fmIsSelectValueFunc(int32_t funcId) {
diff --git a/tests/system-test/2-query/countAlwaysReturnValue.py b/tests/system-test/2-query/countAlwaysReturnValue.py
new file mode 100644
index 0000000000000000000000000000000000000000..08c5ae104f2a7472423345ee1e52dd3e89d53fd0
--- /dev/null
+++ b/tests/system-test/2-query/countAlwaysReturnValue.py
@@ -0,0 +1,115 @@
+import taos
+import sys
+import datetime
+import inspect
+
+from util.log import *
+from util.sql import *
+from util.cases import *
+import random
+
+
+class TDTestCase:
+    updatecfgDict = {"countAlwaysReturnValue":0}
+
+    def init(self, conn, logSql, replicaVar=1):
+        tdLog.debug(f"start to excute {__file__}")
+        tdSql.init(conn.cursor(), False)
+
+    def prepare_data(self, dbname="db"):
+        tdSql.execute(
+            f"create database if not exists {dbname} keep 3650 duration 1000")
+        tdSql.execute(f"use {dbname} ")
+        tdSql.execute(
+            f"create table {dbname}.tb (ts timestamp, c0 int)"
+        )
+        tdSql.execute(
+            f"create table {dbname}.stb (ts timestamp, c0 int) tags (t0 int)"
+        )
+        tdSql.execute(
+            f"create table {dbname}.ctb1 using {dbname}.stb tags (1)"
+        )
+        tdSql.execute(
+            f"create table {dbname}.ctb2 using {dbname}.stb tags (2)"
+        )
+
+        tdSql.execute(
+            f"insert into {dbname}.tb values (now(), NULL)")
+
+        tdSql.execute(
+            f"insert into {dbname}.ctb1 values (now(), NULL)")
+
+        tdSql.execute(
+            f"insert into {dbname}.ctb2 values (now() + 1s, NULL)")
+
+    def test_results(self, dbname="db"):
+
+        # count
+        tdSql.query(f"select count(c0) from {dbname}.tb")
+        tdSql.checkRows(0)
+
+        tdSql.query(f"select count(NULL) from {dbname}.tb")
+        tdSql.checkRows(0)
+
+        tdSql.query(f"select c0,count(c0) from {dbname}.tb group by c0")
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 0, None)
+
+        tdSql.query(f"select count(c0) from {dbname}.stb")
+        tdSql.checkRows(0)
+
+        tdSql.query(f"select count(NULL) from {dbname}.stb")
+        tdSql.checkRows(0)
+
+        tdSql.query(f"select c0,count(c0) from {dbname}.stb group by c0")
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 0, None)
+
+        tdSql.query(f"select count(NULL)")
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 0, 0)
+
+        # hyperloglog
+        tdSql.query(f"select hyperloglog(c0) from {dbname}.tb")
+        tdSql.checkRows(0)
+
+        tdSql.query(f"select hyperloglog(NULL) from {dbname}.tb")
+        tdSql.checkRows(0)
+
+        tdSql.query(f"select c0,hyperloglog(c0) from {dbname}.tb group by c0")
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 0, None)
+
+        tdSql.query(f"select hyperloglog(c0) from {dbname}.stb")
+        tdSql.checkRows(0)
+
+        tdSql.query(f"select hyperloglog(NULL) from {dbname}.stb")
+        tdSql.checkRows(0)
+
+        tdSql.query(f"select c0,hyperloglog(c0) from {dbname}.stb group by c0")
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 0, None)
+
+        tdSql.query(f"select hyperloglog(NULL)")
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 0, 0)
+
+    def run(self):
+        tdSql.prepare()
+
+        tdLog.printNoPrefix("==========step1:prepare data ==============")
+
+        self.prepare_data()
+
+        tdLog.printNoPrefix("==========step2:test results ==============")
+
+        self.test_results()
+
+
+    def stop(self):
+        tdSql.close()
+        tdLog.success(f"{__file__} successfully executed")
+
+
+tdCases.addLinux(__file__, TDTestCase())
+tdCases.addWindows(__file__, TDTestCase())
diff --git a/tests/system-test/2-query/hyperloglog.py b/tests/system-test/2-query/hyperloglog.py
index d2cbe07b6571c9e0a0b737ce0ae40ae4ed1e1642..b6779509487f12824518cb5ba553d7681466686c 100644
--- a/tests/system-test/2-query/hyperloglog.py
+++ b/tests/system-test/2-query/hyperloglog.py
@@ -28,7 +28,7 @@ ALL_COL = [ INT_COL, BINT_COL, SINT_COL, TINT_COL, FLOAT_COL, DOUBLE_COL, BOOL_C
 DBNAME = "db"
 
 class TDTestCase:
-    
+
     updatecfgDict = {"maxTablesPerVnode":2 ,"minTablesPerVnode":2,"tableIncStepPerVnode":2 }
 
     def init(self, conn, logSql, replicaVar=1):
diff --git a/tests/system-test/fulltest.sh b/tests/system-test/fulltest.sh
index 03ac0e0fb6bba2590b9f60958e0d2d358283c30f..622dbba22316719e6ae874f6ce362663d22fb3a4 100755
--- a/tests/system-test/fulltest.sh
+++ b/tests/system-test/fulltest.sh
@@ -17,7 +17,7 @@ python3 ./test.py -f 0-others/taosdShell.py -N 5 -M 3 -Q 3
 python3 ./test.py -f 0-others/sysinfo.py
 python3 ./test.py -f 0-others/user_control.py
 python3 ./test.py -f 0-others/fsync.py
-python3 ./test.py  -f 0-others/compatibility.py   
+python3 ./test.py  -f 0-others/compatibility.py
 python3 ./test.py -f 1-insert/alter_database.py
 python3 ./test.py -f 1-insert/influxdb_line_taosc_insert.py
 python3 ./test.py -f 1-insert/opentsdb_telnet_line_taosc_insert.py
@@ -76,6 +76,8 @@ python3 ./test.py -f 2-query/count_partition.py
 python3 ./test.py -f 2-query/count_partition.py -R
 python3 ./test.py -f 2-query/count.py
 python3 ./test.py -f 2-query/count.py -R
+python3 ./test.py -f 2-query/countAlwaysReturnValue.py
+python3 ./test.py -f 2-query/countAlwaysReturnValue.py -R
 python3 ./test.py -f 2-query/db.py
 python3 ./test.py -f 2-query/db.py -R
 python3 ./test.py -f 2-query/diff.py
@@ -385,6 +387,7 @@ python3 ./test.py -f 2-query/Today.py -Q 2
 python3 ./test.py -f 2-query/max.py -Q 2
 python3 ./test.py -f 2-query/min.py -Q 2
 python3 ./test.py -f 2-query/count.py -Q 2
+python3 ./test.py -f 2-query/countAlwaysReturnValue.py -Q 2
 python3 ./test.py -f 2-query/last.py -Q 2
 python3 ./test.py -f 2-query/first.py -Q 2
 python3 ./test.py -f 2-query/To_iso8601.py -Q 2
@@ -480,6 +483,7 @@ python3 ./test.py -f 2-query/Today.py -Q  3
 python3 ./test.py -f 2-query/max.py -Q  3
 python3 ./test.py -f 2-query/min.py -Q  3
 python3 ./test.py -f 2-query/count.py -Q  3
+python3 ./test.py -f 2-query/countAlwaysReturnValue.py -Q 3
 python3 ./test.py -f 2-query/last.py -Q  3
 python3 ./test.py -f 2-query/first.py -Q  3
 python3 ./test.py -f 2-query/To_iso8601.py -Q  3
@@ -577,6 +581,7 @@ python3 ./test.py -f 2-query/Today.py -Q  4
 python3 ./test.py -f 2-query/max.py -Q  4
 python3 ./test.py -f 2-query/min.py -Q  4
 python3 ./test.py -f 2-query/count.py -Q  4
+python3 ./test.py -f 2-query/countAlwaysReturnValue.py -Q 4
 python3 ./test.py -f 2-query/last.py -Q  4
 python3 ./test.py -f 2-query/first.py -Q  4
 python3 ./test.py -f 2-query/To_iso8601.py -Q  4
@@ -592,7 +597,7 @@ python3 ./test.py -f 2-query/apercentile.py -Q  4
 python3 ./test.py -f 2-query/abs.py -Q  4
 python3 ./test.py -f 2-query/ceil.py -Q  4
 python3 ./test.py -f 2-query/floor.py -Q  4
-python3 ./test.py -f 2-query/round.py -Q  4 
+python3 ./test.py -f 2-query/round.py -Q  4
 python3 ./test.py -f 2-query/log.py -Q  4
 python3 ./test.py -f 2-query/pow.py -Q  4
 python3 ./test.py -f 2-query/sqrt.py -Q  4