diff --git a/src/share/aggregate/first_row.h b/src/share/aggregate/first_row.h
index 0c960bfd7e..fa6b6cf2d1 100644
--- a/src/share/aggregate/first_row.h
+++ b/src/share/aggregate/first_row.h
@@ -108,6 +108,41 @@ public:
     return ret;
   }
 
+  inline int add_one_row(RuntimeContext &agg_ctx, int64_t batch_idx, int64_t batch_size,
+                         const bool is_null, const char *data, const int32_t data_len,
+                         int32_t agg_col_idx, char *agg_cell) override
+  {
+    int ret = OB_SUCCESS;
+    NotNullBitVector &not_nulls = agg_ctx.locate_notnulls_bitmap(agg_col_idx, agg_cell);
+    if (OB_LIKELY(not_nulls.at(agg_col_idx))) {
+      // already copied
+    } else if (!is_null) {
+      if (data_len > 0) {
+        if (OB_ISNULL(data)) {
+          ret = OB_INVALID_ARGUMENT;
+          SQL_LOG(WARN, "invalid null payload", K(ret));
+        } else {
+          void *tmp_buf = agg_ctx.allocator_.alloc(data_len);
+          if (OB_ISNULL(tmp_buf)) {
+            ret = OB_ALLOCATE_MEMORY_FAILED;
+            SQL_LOG(WARN, "allocate memory failed", K(ret));
+          } else {
+            MEMCPY(tmp_buf, data, data_len);
+            // store data ptr and len
+            agg_ctx.set_agg_cell((char *)tmp_buf, data_len, agg_col_idx, agg_cell);
+          }
+        }
+      } else {
+        agg_ctx.set_agg_cell(nullptr, data_len, agg_col_idx, agg_cell);
+      }
+      not_nulls.set(agg_col_idx);
+    } else {
+      agg_ctx.set_agg_cell(nullptr, INT32_MAX, agg_col_idx, agg_cell);
+      not_nulls.set(agg_col_idx);
+    }
+    return ret;
+  }
+
   template <typename ColumnFmt>
   inline int collect_group_result(RuntimeContext &agg_ctx, const sql::ObExpr &agg_expr,
                                   const int32_t agg_col_id, const char *agg_cell,
diff --git a/src/share/aggregate/iaggregate.h b/src/share/aggregate/iaggregate.h
index a14ccb5f8b..7fe2ae5534 100644
--- a/src/share/aggregate/iaggregate.h
+++ b/src/share/aggregate/iaggregate.h
@@ -89,18 +89,6 @@ public:
     return 0;
   }
 
-  inline int add_one_row(RuntimeContext &agg_ctx, int64_t batch_idx, int64_t batch_size,
-                         const bool is_null, const char *data, const int32_t data_len,
-                         int32_t agg_col_idx, char *agg_cell) override
-  {
-    UNUSEDx(is_null, data, data_len);
-    int ret = OB_SUCCESS;
-    sql::EvalBound bound(batch_size, batch_idx, batch_idx + 1, true);
-    char mock_skip_data[1] = {0};
-    ObBitVector &mock_skip = *to_bit_vector(mock_skip_data);
-    return static_cast<Derived *>(this)->add_batch_rows(agg_ctx, agg_col_idx, mock_skip, bound,
-                                                        agg_cell);
-  }
   int add_batch_rows(RuntimeContext &agg_ctx, const int32_t agg_col_id,
                      const sql::ObBitVector &skip, const sql::EvalBound &bound, char *agg_cell,
                      const RowSelector row_sel = RowSelector{}) override
@@ -709,6 +697,17 @@ public:
     return OB_SUCCESS;
   }
 
+  inline int add_one_row(RuntimeContext &agg_ctx, int64_t batch_idx, int64_t batch_size,
+                         const bool is_null, const char *data, const int32_t data_len,
+                         int32_t agg_col_idx, char *agg_cell) override
+  {
+    // FIXME: opt performance
+    sql::EvalBound bound(batch_size, batch_idx, batch_idx + 1, true);
+    char mock_skip_data[1] = {0};
+    ObBitVector &mock_skip = *to_bit_vector(mock_skip_data);
+    return static_cast<Aggregate *>(agg_)->add_batch_rows(agg_ctx, agg_col_idx, mock_skip, bound,
+                                                          agg_cell);
+  }
   void reuse() override
   {
     if (agg_ != NULL) {
diff --git a/src/share/aggregate/processor.cpp b/src/share/aggregate/processor.cpp
index 8a26e885ca..5a29c41820 100644
--- a/src/share/aggregate/processor.cpp
+++ b/src/share/aggregate/processor.cpp
@@ -654,11 +654,19 @@ int Processor::prepare_adding_one_row()
     for (int i = 0; OB_SUCC(ret) && i < agg_ctx_.aggr_infos_.count(); i++) {
       ObAggrInfo &info = agg_ctx_.aggr_infos_.at(i);
       add_one_row_fn fn_ptr = nullptr;
-      if (info.param_exprs_.count() <= 0 || info.param_exprs_.count() > 1) {
+      if ((info.param_exprs_.count() <= 0 && !info.is_implicit_first_aggr())
+          || info.param_exprs_.count() > 1) {
         fn_ptr = aggregate::add_one_row<ObVectorBase>;
       } else {
-        ObDatumMeta meta = info.param_exprs_.at(0)->datum_meta_;
-        VectorFormat fmt = info.param_exprs_.at(0)->get_format(agg_ctx_.eval_ctx_);
+        ObDatumMeta meta;
+        VectorFormat fmt;
+        if (info.is_implicit_first_aggr()) {
+          meta = info.expr_->datum_meta_;
+          fmt = info.expr_->get_format(agg_ctx_.eval_ctx_);
+        } else {
+          meta = info.param_exprs_.at(0)->datum_meta_;
+          fmt = info.param_exprs_.at(0)->get_format(agg_ctx_.eval_ctx_);
+        }
         VecValueTypeClass vec_tc = get_vec_value_tc(meta.type_, meta.scale_, meta.precision_);
         switch(fmt) {
           case common::VEC_UNIFORM: {
diff --git a/src/share/aggregate/processor.h b/src/share/aggregate/processor.h
index 88b586d2ec..6a33a441cb 100644
--- a/src/share/aggregate/processor.h
+++ b/src/share/aggregate/processor.h
@@ -1,4 +1,4 @@
-/**get
+/**
  * Copyright (c) 2021 OceanBase
  * OceanBase CE is licensed under Mulan PubL v2.
  * You can use this software according to the terms and conditions of the Mulan PubL v2.
diff --git a/src/share/aggregate/single_row.h b/src/share/aggregate/single_row.h
index a601bc645c..8e566f37fb 100644
--- a/src/share/aggregate/single_row.h
+++ b/src/share/aggregate/single_row.h
@@ -94,6 +94,29 @@ public:
     }
     return ret;
   }
+  inline int add_one_row(RuntimeContext &agg_ctx, int64_t batch_idx, int64_t batch_size,
+                         const bool is_null, const char *data, const int32_t data_len,
+                         int32_t agg_col_idx, char *agg_cell) override
+  {
+    int ret = OB_SUCCESS;
+    AggrRowPtr agg_row = agg_ctx.agg_rows_.at(batch_idx);
+    NotNullBitVector &notnulls = agg_ctx.row_meta().locate_notnulls_bitmap(agg_row);
+    if (agg_func != T_FUN_COUNT) {
+      if (OB_LIKELY(!is_null)) {
+        char *cell = agg_ctx.row_meta().locate_cell_payload(agg_col_idx, agg_row);
+        if (helper::is_var_len_agg_cell(in_tc)) {
+          *reinterpret_cast<int64_t *>(cell) = reinterpret_cast<int64_t>(data);
+          *reinterpret_cast<int32_t *>(cell + sizeof(char *)) = data_len;
+        } else {
+          MEMCPY(cell, data, data_len);
+        }
+        notnulls.set(agg_col_idx);
+      }
+    } else if (!is_null) { // COUNT function, only need to set not null
+      notnulls.set(agg_col_idx);
+    }
+    return ret;
+  }
   template <typename ColumnFmt>
   inline int add_row(RuntimeContext &agg_ctx, ColumnFmt &columns, const int32_t row_num,
                      const int32_t agg_col_id, char *agg_cell, void *tmp_res, int64_t &calc_info)
diff --git a/src/sql/engine/aggregate/ob_hash_groupby_vec_op.cpp b/src/sql/engine/aggregate/ob_hash_groupby_vec_op.cpp
index 1593c563f4..301d7d8df6 100644
--- a/src/sql/engine/aggregate/ob_hash_groupby_vec_op.cpp
+++ b/src/sql/engine/aggregate/ob_hash_groupby_vec_op.cpp
@@ -1080,6 +1080,8 @@ int ObHashGroupByVecOp::load_data_batch(int64_t max_row_cnt)
         for (int64_t i = 0; i < MY_SPEC.aggr_infos_.count(); ++i) {
           if (MY_SPEC.aggr_infos_.at(i).param_exprs_.count() == 1) {
             aggr_vectors_[i] = MY_SPEC.aggr_infos_.at(i).param_exprs_.at(0)->get_vector(eval_ctx_);
+          } else if (MY_SPEC.aggr_infos_.at(i).is_implicit_first_aggr()) {
+            aggr_vectors_[i] = MY_SPEC.aggr_infos_.at(i).expr_->get_vector(eval_ctx_);
           } else {
             aggr_vectors_[i] = nullptr;
           }