diff --git a/src/client/src/tscSQLParser.c b/src/client/src/tscSQLParser.c
index 1a3817d7a02523a3d8316dc54bfffbf07c1abe77..26903ed428443ec6edb13726e85231d31a0bb9f2 100644
--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@@ -2819,7 +2819,8 @@ int32_t addExprAndResultField(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, int32_t col
     case TSDB_FUNC_ELAPSED:
     case TSDB_FUNC_MODE:
     case TSDB_FUNC_STATE_COUNT:
-    case TSDB_FUNC_STATE_DURATION:{
+    case TSDB_FUNC_STATE_DURATION:
+    case TSDB_FUNC_HYPERLOGLOG:{
       // 1. valid the number of parameters
       int32_t numOfParams =
           (pItem->pNode->Expr.paramList == NULL) ? 0 : (int32_t)taosArrayGetSize(pItem->pNode->Expr.paramList);
@@ -2890,7 +2891,8 @@ int32_t addExprAndResultField(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, int32_t col
       if (functionId == TSDB_FUNC_MODE && pColumnSchema->colId == PRIMARYKEY_TIMESTAMP_COL_INDEX &&
           pColumnSchema->type == TSDB_DATA_TYPE_TIMESTAMP){
         return invalidOperationMsg(tscGetErrorMsgPayload(pCmd), msg29);
-      } else if (!IS_NUMERIC_TYPE(pSchema->type) && (functionId != TSDB_FUNC_ELAPSED) && (functionId != TSDB_FUNC_MODE)) {
+      } else if (!IS_NUMERIC_TYPE(pSchema->type) && (functionId != TSDB_FUNC_ELAPSED) &&
+                 (functionId != TSDB_FUNC_MODE) && (functionId != TSDB_FUNC_HYPERLOGLOG)) {
         return invalidOperationMsg(tscGetErrorMsgPayload(pCmd), msg1);
       } else if (IS_UNSIGNED_NUMERIC_TYPE(pSchema->type) &&
                  (functionId == TSDB_FUNC_DIFF || functionId == TSDB_FUNC_DERIVATIVE)) {
diff --git a/src/query/inc/qAggMain.h b/src/query/inc/qAggMain.h
index 0b87c546d570e8bf4dfc723ae9dc380442009280..1c07505b09b4bb1872c39414afd677456657d7c7 100644
--- a/src/query/inc/qAggMain.h
+++ b/src/query/inc/qAggMain.h
@@ -86,8 +86,9 @@ extern "C" {
 #define TSDB_FUNC_WSTART          44
 #define TSDB_FUNC_WSTOP           45
 #define TSDB_FUNC_WDURATION       46
+#define TSDB_FUNC_HYPERLOGLOG     47
 
-#define TSDB_FUNC_MAX_NUM         47
+#define TSDB_FUNC_MAX_NUM         48
 
 #define TSDB_FUNCSTATE_SO           0x1u    // single output
 #define TSDB_FUNCSTATE_MO           0x2u    // dynamic number of output, not multinumber of output e.g., TOP/BOTTOM
diff --git a/src/query/src/qAggMain.c b/src/query/src/qAggMain.c
index bc403b8b51e10de2081bb9b280c1be2a0a95f896..821ca88d1ad06250ac5c2443e031252a735d4023 100644
--- a/src/query/src/qAggMain.c
+++ b/src/query/src/qAggMain.c
@@ -29,6 +29,7 @@
 #include "queryLog.h"
 #include "qUdf.h"
 #include "tcompare.h"
+#include "hashfunc.h"
 
 #define GET_INPUT_DATA_LIST(x) ((char *)((x)->pInput))
 #define GET_INPUT_DATA(x, y) (GET_INPUT_DATA_LIST(x) + (y) * (x)->inputBytes)
@@ -256,11 +257,160 @@ typedef struct {
   char     data[];
 } TailUnit;
 
-typedef struct STailInfo {
+typedef struct {
   int32_t      num;
   TailUnit     **res;
 } STailInfo;
 
+static void *getOutputInfo(SQLFunctionCtx *pCtx) {
+  SResultRowCellInfo *pResInfo = GET_RES_INFO(pCtx);
+
+  // only the first_stage_merge is directly written data into final output buffer
+  if (pCtx->stableQuery && pCtx->currentStage != MERGE_STAGE) {
+    return pCtx->pOutput;
+  } else { // during normal table query and super table at the secondary_stage, result is written to intermediate buffer
+    return GET_ROWCELL_INTERBUF(pResInfo);
+  }
+}
+
+/* hyperloglog start */
+#define HLL_BUCKET_BITS 14 // The bits of the bucket
+#define HLL_DATA_BITS (64-HLL_BUCKET_BITS)
+#define HLL_BUCKETS (1<<HLL_BUCKET_BITS)
+#define HLL_BUCKET_MASK (HLL_BUCKETS-1)
+#define HLL_ALPHA_INF 0.721347520444481703680 // constant for 0.5/ln(2)
+
+typedef struct {
+  uint8_t buckets[HLL_BUCKETS]; // Data bytes.
+} SHLLInfo;
+
+static void hllBucketHisto(uint8_t *buckets, int* bucketHisto) {
+  uint64_t *word = (uint64_t*) buckets;
+  uint8_t *bytes;
+  int j;
+
+  for (j = 0; j < HLL_BUCKETS/8; j++) {
+    if (*word == 0) {
+      bucketHisto[0] += 8;
+    } else {
+      bytes = (uint8_t*) word;
+      bucketHisto[bytes[0]]++;
+      bucketHisto[bytes[1]]++;
+      bucketHisto[bytes[2]]++;
+      bucketHisto[bytes[3]]++;
+      bucketHisto[bytes[4]]++;
+      bucketHisto[bytes[5]]++;
+      bucketHisto[bytes[6]]++;
+      bucketHisto[bytes[7]]++;
+    }
+    word++;
+  }
+}
+static double hllTau(double x) {
+  if (x == 0. || x == 1.) return 0.;
+  double zPrime;
+  double y = 1.0;
+  double z = 1 - x;
+  do {
+    x = sqrt(x);
+    zPrime = z;
+    y *= 0.5;
+    z -= pow(1 - x, 2)*y;
+  } while(zPrime != z);
+  return z / 3;
+}
+
+static double hllSigma(double x) {
+  if (x == 1.) return INFINITY;
+  double zPrime;
+  double y = 1;
+  double z = x;
+  do {
+    x *= x;
+    zPrime = z;
+    z += x * y;
+    y += y;
+  } while(zPrime != z);
+  return z;
+}
+
+static uint64_t hllCountCnt(uint8_t *buckets) {
+  double m = HLL_BUCKETS;
+  int buckethisto[64] = {0};
+  hllBucketHisto(buckets,buckethisto);
+
+  double z = m * hllTau((m-buckethisto[HLL_DATA_BITS+1])/(double)m);
+  for (int j = HLL_DATA_BITS; j >= 1; --j) {
+    z += buckethisto[j];
+    z *= 0.5;
+  }
+  z += m * hllSigma(buckethisto[0]/(double)m);
+  double E = llroundl(HLL_ALPHA_INF*m*m/z);
+
+  return (uint64_t) E;
+}
+
+static int hllCountNum(void *ele, int32_t elesize, int32_t *buk) {
+  uint64_t hash, bit, index;
+  int count;
+
+  hash = MurmurHash3_64(ele,elesize);
+  index = hash & HLL_BUCKET_MASK;
+  hash >>= HLL_BUCKET_BITS;
+  hash |= ((uint64_t)1<<HLL_DATA_BITS);
+  bit = 1;
+  count = 1;
+  while((hash & bit) == 0) {
+    count++;
+    bit <<= 1;
+  }
+  *buk = (int32_t) index;
+  return count;
+}
+
+static void hll_function(SQLFunctionCtx *pCtx) {
+  SHLLInfo *pHLLInfo = getOutputInfo(pCtx);
+  for (int32_t i = 0; i < pCtx->size; ++i) {
+    char *val = GET_INPUT_DATA(pCtx, i);
+    if (isNull(val, pCtx->inputType)) {
+      continue;
+    }
+    int32_t elesize = pCtx->inputBytes;
+    if(IS_VAR_DATA_TYPE(pCtx->inputType)) {
+      elesize = varDataLen(val);
+      val = varDataVal(val);
+    }
+    int32_t index;
+    uint8_t count = hllCountNum(val,elesize,&index);
+    uint8_t oldcount = pHLLInfo->buckets[index];
+    if (count > oldcount) {
+      pHLLInfo->buckets[index] = count;
+    }
+  }
+  GET_RES_INFO(pCtx)->numOfRes = 1;
+}
+
+static void hll_func_merge(SQLFunctionCtx *pCtx) {
+  SResultRowCellInfo *pResInfo = GET_RES_INFO(pCtx);
+  SHLLInfo *pHLLInfo = (SHLLInfo *)GET_ROWCELL_INTERBUF(pResInfo);
+
+  SHLLInfo *pData = (SHLLInfo *)GET_INPUT_DATA_LIST(pCtx);
+  for (int i = 0; i < HLL_BUCKETS; i++) {
+    if (pData->buckets[i] > pHLLInfo->buckets[i]) {
+      pHLLInfo->buckets[i] = pData->buckets[i];
+    }
+  }
+}
+
+static void hll_func_finalizer(SQLFunctionCtx *pCtx) {
+  SHLLInfo *pInfo = GET_ROWCELL_INTERBUF(GET_RES_INFO(pCtx));
+
+  GET_RES_INFO(pCtx)->numOfRes = 1;
+  *(uint64_t *)(pCtx->pOutput) = hllCountCnt(pInfo->buckets);
+  doFinalizer(pCtx);
+}
+/* hyperloglog end */
+
 int32_t getResultDataInfo(int32_t dataType, int32_t dataBytes, int32_t functionId, int32_t param, int16_t *type,
                           int32_t *bytes, int32_t *interBytes, int16_t extLength, bool isSuperTable, SUdfInfo* pUdfInfo) {
   if (!isValidDataType(dataType)) {
@@ -334,6 +484,13 @@ 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;
@@ -2403,18 +2560,6 @@ static void copyTopBotRes(SQLFunctionCtx *pCtx, int32_t type) {
   tfree(pData);
 }
 
-static void *getOutputInfo(SQLFunctionCtx *pCtx) {
-  SResultRowCellInfo *pResInfo = GET_RES_INFO(pCtx);
-
-  // only the first_stage_merge is directly written data into final output buffer
-  if (pCtx->stableQuery && pCtx->currentStage != MERGE_STAGE) {
-    return pCtx->pOutput;
-  } else { // during normal table query and super table at the secondary_stage, result is written to intermediate buffer
-    return GET_ROWCELL_INTERBUF(pResInfo);
-  }
-}
-
-
 /*
  * keep the intermediate results during scan data blocks in the format of:
  * +-----------------------------------+-------------one value pair-----------+------------next value pair-----------+
@@ -5815,6 +5960,7 @@ static void wduration_function(SQLFunctionCtx *pCtx) {
   }
   *(int64_t *)(pCtx->pOutput) = duration;
 }
+
 /////////////////////////////////////////////////////////////////////////////////////////////
 /*
  * function compatible list.
@@ -5835,8 +5981,8 @@ int32_t functionCompatList[] = {
     1,              1,              1,         1,         -1,           1,          1,           1,           5,         1,      1,
     // tid_tag,     deriv,          csum,      mavg,      sample,       block_info, elapsed,     histogram,   unique,    mode,   tail
     6,              8,              -1,        -1,        -1,           7,          1,           -1,          -1,        1,      -1,
-    // stateCount,  stateDuration,  wstart,    wstop,     wduration,
-    1,              1,              1,         1,         1,
+    // stateCount,  stateDuration,  wstart,    wstop,     wduration,    hyperloglog
+    1,              1,              1,         1,         1,            1
 };
 
 SAggFunctionInfo aAggs[TSDB_FUNC_MAX_NUM] = {{
@@ -6405,5 +6551,17 @@ SAggFunctionInfo aAggs[TSDB_FUNC_MAX_NUM] = {{
                               doFinalizer,
                               copy_function,
                               dataBlockRequired,
+                          },
+                          {
+                              // 47
+                              "hyperloglog",
+                              TSDB_FUNC_HYPERLOGLOG,
+                              TSDB_FUNC_HYPERLOGLOG,
+                              TSDB_BASE_FUNC_SO,
+                              function_setup,
+                              hll_function,
+                              hll_func_finalizer,
+                              hll_func_merge,
+                              dataBlockRequired,
                           }
 };
diff --git a/src/util/inc/hashfunc.h b/src/util/inc/hashfunc.h
index 529188849846088106f6576242ef76e2894ccb1b..55835a60c92dc641cdef0f9bb75aa631aac4fddd 100644
--- a/src/util/inc/hashfunc.h
+++ b/src/util/inc/hashfunc.h
@@ -33,7 +33,8 @@ typedef void (*_hash_free_fn_t)(void *param);
  */
 uint32_t MurmurHash3_32(const char *key, uint32_t len);
 
-/**
+uint64_t MurmurHash3_64(const void *key, uint32_t len);
+    /**
  *
  * @param key
  * @param len
diff --git a/src/util/src/thashutil.c b/src/util/src/thashutil.c
index 4a0208a3d0bf22f21b5f6a05513f435664e746af..545a91daf5f6ebd3721f6d005750f9cf235939cf 100644
--- a/src/util/src/thashutil.c
+++ b/src/util/src/thashutil.c
@@ -78,6 +78,42 @@ uint32_t MurmurHash3_32(const char *key, uint32_t len) {
   return h1;
 }
 
+uint64_t MurmurHash3_64(const void *key, uint32_t len) {
+  const uint64_t m = 0x87c37b91114253d5;
+  const int r = 47;
+  uint32_t seed = 0x12345678;
+  uint64_t h = seed ^ (len * m);
+  const uint8_t *data = (const uint8_t *)key;
+  const uint8_t *end = data + (len-(len&7));
+
+  while(data != end) {
+    uint64_t k = *((uint64_t*)data);
+
+    k *= m;
+    k ^= k >> r;
+    k *= m;
+    h ^= k;
+    h *= m;
+    data += 8;
+  }
+
+  switch(len & 7) {
+    case 7: h ^= (uint64_t)data[6] << 48; /* fall-thru */
+    case 6: h ^= (uint64_t)data[5] << 40; /* fall-thru */
+    case 5: h ^= (uint64_t)data[4] << 32; /* fall-thru */
+    case 4: h ^= (uint64_t)data[3] << 24; /* fall-thru */
+    case 3: h ^= (uint64_t)data[2] << 16; /* fall-thru */
+    case 2: h ^= (uint64_t)data[1] << 8; /* fall-thru */
+    case 1: h ^= (uint64_t)data[0];
+      h *= m; /* fall-thru */
+  };
+
+  h ^= h >> r;
+  h *= m;
+  h ^= h >> r;
+  return h;
+}
+
 uint32_t taosIntHash_32(const char *key, uint32_t UNUSED_PARAM(len)) { return *(uint32_t *)key; }
 uint32_t taosIntHash_16(const char *key, uint32_t UNUSED_PARAM(len)) { return *(uint16_t *)key; }
 uint32_t taosIntHash_8(const char *key, uint32_t UNUSED_PARAM(len)) { return *(uint8_t *)key; }