diff --git a/src/query/src/qExecutor.c b/src/query/src/qExecutor.c
index 67a336edd5b764edff17367d2007e5598bfdb1c0..7e89b3a766f0c9124417c65b83dfe55853b0f094 100644
--- a/src/query/src/qExecutor.c
+++ b/src/query/src/qExecutor.c
@@ -1578,9 +1578,6 @@ static void doHashGroupbyAgg(SOperatorInfo* pOperator, SGroupbyOperatorInfo *pIn
   int32_t num = 0;
   for (int32_t j = 0; j < pSDataBlock->info.rows; ++j) {
     char* val = ((char*)pColInfoData->pData) + bytes * j;
-    if (isNull(val, type)) {
-      continue;
-    }
 
     // Compare with the previous row of this column, and do not set the output buffer again if they are identical.
     if (pInfo->prevData == NULL) {
diff --git a/tests/pytest/functions/function_count_last_stab.py b/tests/pytest/functions/function_count_last_stab.py
index 1d777c6bd314941036f542c7d0e9063e590fa7dd..cd0a9b17c2fd8c98544dca09f6a7008929225ece 100644
--- a/tests/pytest/functions/function_count_last_stab.py
+++ b/tests/pytest/functions/function_count_last_stab.py
@@ -42,22 +42,22 @@ class TDTestCase:
                         % (self.ts + i, i + 1, 1, i + 1, i + 1, i + 0.1, i + 0.1, i % 2, i + 1, i + 1, i + 1, i + 1, i + 1, i + 1))            
 
         tdSql.query("select count(*),last(*) from stest  group by col1")
-        tdSql.checkRows(10)
-        tdSql.checkData(0, 0, 1)
-        tdSql.checkData(1, 2, 2)
-        tdSql.checkData(1, 3, 1)
+        tdSql.checkRows(11)
+        tdSql.checkData(1, 0, 1)
+        tdSql.checkData(2, 2, 2)
+        tdSql.checkData(2, 3, 1)
 
         tdSql.query("select count(*),last(*) from stest  group by col2")
-        tdSql.checkRows(1)
-        tdSql.checkData(0, 0, 10)
-        tdSql.checkData(0, 2, 10)
-        tdSql.checkData(0, 3, 1)
+        tdSql.checkRows(2)
+        tdSql.checkData(1, 0, 10)
+        tdSql.checkData(1, 2, 10)
+        tdSql.checkData(1, 3, 1)
 
         tdSql.query("select count(*),last(ts,stest.*) from stest  group by col1")
-        tdSql.checkRows(10)
-        tdSql.checkData(0, 0, 1)
-        tdSql.checkData(0, 2, "2018-09-17 09:00:00")
-        tdSql.checkData(1, 4, 1)
+        tdSql.checkRows(11)
+        tdSql.checkData(1, 0, 1)
+        tdSql.checkData(1, 2, "2018-09-17 09:00:00")
+        tdSql.checkData(2, 4, 1)
 
 
                 
diff --git a/tests/script/general/parser/col_arithmetic_query.sim b/tests/script/general/parser/col_arithmetic_query.sim
index 502de9583e9727d2dbee4a5601f974d6a46173ba..9b0dc8e964cf39909b803fe5ea20a7bdff8ceb59 100644
--- a/tests/script/general/parser/col_arithmetic_query.sim
+++ b/tests/script/general/parser/col_arithmetic_query.sim
@@ -561,19 +561,19 @@ endi
 sql_error select first(c6) - last(c6) *12 / count(*) from $stb group by c3;
 
 sql select first(c6) - last(c6) *12 / count(*) from $stb group by c5;
-if $rows != 10 then
+if $rows != 11 then
   return -1
 endi
 
-if $data00 != 0.000000000 then
+if $data00 != -0.002160000 then
   return -1
 endi
 
-if $data10 != 0.997600000 then
+if $data10 != 0.000000000 then
   return -1
 endi
 
-if $data90 != 8.978400000 then
+if $data90 != 7.980800000 then
   return -1
 endi