diff --git a/src/query/src/qAggMain.c b/src/query/src/qAggMain.c
index 39deb31896fa45adedf0561a1d0915643be36e20..7f94a0bf3042194de21c472bba1b91ce4a657626 100644
--- a/src/query/src/qAggMain.c
+++ b/src/query/src/qAggMain.c
@@ -481,13 +481,6 @@ int32_t getResultDataInfo(int32_t dataType, int32_t dataBytes, int32_t functionI
     return TSDB_CODE_SUCCESS;
   }
 
-  if (functionId == TSDB_FUNC_HYPERLOGLOG) {
-    *type = TSDB_DATA_TYPE_UBIGINT;
-    *bytes = sizeof(uint64_t);
-    *interBytes = sizeof(SHLLInfo);
-    return TSDB_CODE_SUCCESS;
-  }
-
   if (functionId == TSDB_FUNC_CSUM) {
     if (IS_SIGNED_NUMERIC_TYPE(dataType)) {
       *type = TSDB_DATA_TYPE_BIGINT;
@@ -582,6 +575,11 @@ int32_t getResultDataInfo(int32_t dataType, int32_t dataBytes, int32_t functionI
       *bytes = (sizeof(STailInfo) + (sizeof(TailUnit) + dataBytes + POINTER_BYTES + extLength) * param);
       *interBytes = *bytes;
 
+      return TSDB_CODE_SUCCESS;
+    } else if (functionId == TSDB_FUNC_HYPERLOGLOG) {
+      *type = TSDB_DATA_TYPE_BINARY;
+      *bytes = sizeof(SHLLInfo);
+      *interBytes = sizeof(SHLLInfo);
       return TSDB_CODE_SUCCESS;
     } else if (functionId == TSDB_FUNC_SAMPLE) {
       *type = TSDB_DATA_TYPE_BINARY;
@@ -738,11 +736,15 @@ int32_t getResultDataInfo(int32_t dataType, int32_t dataBytes, int32_t functionI
 
     // the output column may be larger than sizeof(STopBotInfo)
     *interBytes = (int32_t)size;
+  } else if (functionId == TSDB_FUNC_HYPERLOGLOG) {
+    *type = TSDB_DATA_TYPE_UBIGINT;
+    *bytes = sizeof(uint64_t);
+    *interBytes = sizeof(SHLLInfo);
   } else if (functionId == TSDB_FUNC_SAMPLE) {
-      *type = (int16_t)dataType;
-      *bytes = dataBytes;
-      size_t size = sizeof(SSampleFuncInfo) + dataBytes*param + sizeof(int64_t)*param + extLength*param;
-      *interBytes = (int32_t)size;
+    *type = (int16_t)dataType;
+    *bytes = dataBytes;
+    size_t size = sizeof(SSampleFuncInfo) + dataBytes*param + sizeof(int64_t)*param + extLength*param;
+    *interBytes = (int32_t)size;
   } else if (functionId == TSDB_FUNC_LAST_ROW) {
     *type = (int16_t)dataType;
     *bytes = dataBytes;
diff --git a/tests/develop-test/2-query/function_hll.py b/tests/develop-test/2-query/function_hll.py
new file mode 100644
index 0000000000000000000000000000000000000000..acbefe5a0458fd1cb65d92eb64f844f9ae1ad966
--- /dev/null
+++ b/tests/develop-test/2-query/function_hll.py
@@ -0,0 +1,229 @@
+###################################################################
+#  Copyright (c) 2021 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 -*-
+
+import sys
+from util.log import *
+from util.cases import *
+from util.sql import *
+
+
+class TDTestCase:
+    def caseDescription(self):
+        '''
+        case1<markwang>: [TD-13893] hyperloglog unique
+        '''
+        return
+
+    def init(self, conn, logSql):
+        tdLog.debug("start to execute %s" % __file__)
+        tdSql.init(conn.cursor(), logSql)
+        self._conn = conn
+
+    def run(self):
+        print("running {}".format(__file__))
+        tdSql.execute("drop database if exists hll")
+        tdSql.execute("create database if not exists hll")
+        tdSql.execute('use hll')
+
+        tdSql.execute('create table shll (ts timestamp, dbig bigint, dsmall smallint, dbool bool, dtiny tinyint unsigned, dfloat float, ddouble double, dnchar nchar(4093), dbinary binary(64), dtime timestamp) tags (tbinary nchar(4093), tint int)')
+        tdSql.execute('create table hll1 using shll tags ("t1", 1)')
+        tdSql.execute('create table hll2 using shll tags ("t2", 2)')
+
+        tdSql.execute('insert into hll1 values("2021-10-17 00:31:31", 1, -3276, true, 253, 3.32333, 4.984392323, "你好", "sddd", 333) ("2022-01-24 00:31:32", 1, -32767, false, 254, NULL, 4.982392323, "你好吗", "sdf",2323)')
+        tdSql.execute('insert into hll2 values("2021-10-15 00:31:33", 1, NULL, true, 23, 3.4, 4.982392323, "你好吗", "sdf", 333) ("2021-12-24 00:31:34", 2, 32767, NULL, NULL, NULL, 4.982392323, NULL, "sddd", NULL) ("2022-01-01 08:00:05", 19, 3276, true, 2, 3.323222, 4.92323, "试试", "sddd", 1645434434000)')
+        tdSql.execute('insert into hll2 values("2021-10-17 00:31:31", NULL, 32767, true, 123, 3.323232333, 4.2, NULL, NULL, NULL) ("2022-01-01 08:00:06", NULL, NULL, NULL, 35, 3.323232333, NULL, "试试", NULL, 1645434434000) ("2022-01-01 08:00:07", 9, 54, true, 25, 3.32333, NULL, "试试", NULL, 1645434434001)')
+
+        ## test normal table
+        tdSql.query('select hyperloglog(ts) from hll2')
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 0, 6)
+
+        tdSql.query('select hyperloglog(dbig) from hll2')
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 0, 4)
+
+        tdSql.query('select hyperloglog(dsmall) from hll2')
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 0, 3)
+
+        tdSql.query('select hyperloglog(dbool) from hll2')
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 0, 1)
+
+        tdSql.query('select hyperloglog(dtiny) from hll2')
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 0, 5)
+
+        tdSql.query('select hyperloglog(dfloat) from hll2')
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 0, 4)
+
+        tdSql.query('select hyperloglog(ddouble) from hll2')
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 0, 3)
+
+        tdSql.query('select hyperloglog(dnchar) from hll2')
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 0, 2)
+
+        tdSql.query('select hyperloglog(dbinary) from hll2')
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 0, 2)
+
+        ## test super table
+        tdSql.query('select hyperloglog(dnchar) from shll')
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 0, 3)
+
+        # test group by
+        #group by column
+        tdSql.query('select hyperloglog(dnchar) from shll group by dnchar')
+        tdSql.checkRows(4)
+        tdSql.checkData(0, 0, 0)
+        tdSql.checkData(1, 0, 1)
+        tdSql.checkData(2, 0, 1)
+        tdSql.checkData(3, 0, 1)
+
+        tdSql.query('select hyperloglog(dsmall) from shll group by dnchar')
+        tdSql.checkRows(4)
+        tdSql.checkData(0, 0, 1)
+        tdSql.checkData(1, 0, 1)
+        tdSql.checkData(2, 0, 1)
+        tdSql.checkData(3, 0, 2)
+
+        tdSql.query('select hyperloglog(dsmall) from hll2 group by dnchar')
+        tdSql.checkRows(3)
+        tdSql.checkData(0, 0, 1)
+        tdSql.checkData(1, 0, 0)
+        tdSql.checkData(2, 0, 2)
+
+        #group by tbname
+        tdSql.query('select hyperloglog(dsmall) from shll group by tbname')
+        tdSql.checkRows(2)
+        tdSql.checkData(0, 0, 2)
+        tdSql.checkData(1, 0, 3)
+
+        #group by tag
+        tdSql.query('select hyperloglog(dnchar) from shll group by tint')
+        tdSql.checkRows(2)
+        tdSql.checkData(0, 0, 2)
+        tdSql.checkData(1, 0, 2)
+
+        #test order by
+
+
+        #order by column [desc]
+        tdSql.query('select hyperloglog(dnchar) from shll group by dnchar order by dnchar desc')
+        tdSql.checkRows(4)
+        tdSql.checkData(0, 0, 1)
+        tdSql.checkData(1, 0, 1)
+        tdSql.checkData(2, 0, 1)
+        tdSql.checkData(3, 0, 0)
+
+        #order by tag
+        tdSql.query('select hyperloglog(dsmall) from shll group by tint order by tint desc')
+        tdSql.checkRows(2)
+        tdSql.checkData(0, 0, 3)
+        tdSql.checkData(1, 0, 2)
+
+        # error
+        tdSql.error("select hyperloglog(ts,1) from shll")
+
+        #interval
+        tdSql.query('select hyperloglog(dnchar) from shll interval(1s)')
+        tdSql.checkRows(7)
+        tdSql.checkData(0, 1, 1)
+        tdSql.checkData(1, 1, 1)
+        tdSql.checkData(2, 0, "2021-12-24 00:31:34")
+        tdSql.checkData(2, 1, 0)
+        tdSql.checkData(3, 1, 1)
+        tdSql.checkData(4, 1, 1)
+        tdSql.checkData(5, 1, 1)
+        tdSql.checkData(6, 1, 1)
+
+        tdSql.query('select hyperloglog(dnchar) from shll interval(1w)')
+        tdSql.checkRows(4)
+        tdSql.checkData(0, 1, 2)
+        tdSql.checkData(1, 1, 0)
+        tdSql.checkData(2, 1, 1)
+        tdSql.checkData(3, 1, 1)
+
+
+        #state_window
+        tdSql.query('select hyperloglog(dnchar) from hll2 state_window(dsmall)')
+        tdSql.checkRows(5)
+
+        #session
+        tdSql.query('select hyperloglog(dbinary) from hll2 session(ts,2w)')
+        tdSql.checkRows(2)
+        tdSql.checkData(0, 0, "2021-10-15 00:31:33")
+        tdSql.checkData(0, 1, 1)
+        tdSql.checkData(1, 0, "2021-12-24 00:31:34")
+        tdSql.checkData(1, 1, 1)
+
+        #where
+        tdSql.query('select hyperloglog(dbinary) from shll where dnchar="试试"')
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 0, 1)
+        tdSql.query('select hyperloglog(dbinary) from shll where ts <= "2022-01-01 08:00:05"')
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 0, 2)
+
+        #slimit/soffset
+        tdSql.query('select hyperloglog(dsmall) from shll group by dnchar slimit 2 soffset 2')
+        tdSql.checkRows(2)
+        tdSql.checkData(0, 0, 1)
+        tdSql.checkData(1, 0, 2)
+
+        #limit/offset
+        tdSql.query('select hyperloglog(dnchar) from shll interval(1s) limit 1,3')
+        tdSql.checkRows(3)
+        tdSql.checkData(0, 0, "2021-10-17 00:31:31")
+        tdSql.checkData(0, 1, 1)
+        tdSql.checkData(1, 1, 0)
+        tdSql.checkData(2, 1, 1)
+
+        #having
+        tdSql.query('select hyperloglog(dsmall) from shll group by dnchar having hyperloglog(dsmall)>1')
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 0, 2)
+
+        #subquery
+        tdSql.query('select hyperloglog(dbinary) from (select dbinary from shll where dnchar = "试试")')
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 0, 1)
+
+        #union
+        tdSql.query('select hyperloglog(dtiny) from hll1 union all select hyperloglog(dtiny) from hll2')
+        tdSql.checkRows(2)
+        tdSql.checkData(0, 0, 2)
+        tdSql.checkData(1, 0, 5)
+
+        #join
+        tdSql.execute('create table shll1 (ts timestamp, dbig bigint, dsmall smallint, dbool bool, dtiny tinyint unsigned, dfloat float, ddouble double, dnchar nchar(4093), dbinary binary(64), dtime timestamp) tags (tbinary nchar(4093), tint int)')
+        tdSql.execute('create table hll11 using shll1 tags ("t1", 1)')
+
+        tdSql.execute('insert into hll11 values("2021-10-17 00:31:31", 1, -3276, true, 253, 3.32333, 4.984392323, "你好", "sddd", 333) ("2022-01-24 00:31:32", 1, -32767, false, 254, NULL, 4.982392323, "你好吗", "sdf",2323)')
+
+        tdSql.query('select hyperloglog(shll1.ddouble) from shll, shll1 where shll.ts=shll1.ts and shll.tint=shll1.tint')
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 0, 2)
+
+    def stop(self):
+        tdSql.close()
+        tdLog.success("%s successfully executed" % __file__)
+
+
+tdCases.addWindows(__file__, TDTestCase())
+tdCases.addLinux(__file__, TDTestCase())
+