diff --git a/omnioperator/omniop-hive-extension/src/main/java/com/huawei/boostkit/hive/OmniGroupByOperator.java b/omnioperator/omniop-hive-extension/src/main/java/com/huawei/boostkit/hive/OmniGroupByOperator.java
index 8105b4c1a38579bc59def1225c6e919c01bc46af..d9d54ee15acc7696b582fe9380eaeeeb2b9fcc99 100644
--- a/omnioperator/omniop-hive-extension/src/main/java/com/huawei/boostkit/hive/OmniGroupByOperator.java
+++ b/omnioperator/omniop-hive-extension/src/main/java/com/huawei/boostkit/hive/OmniGroupByOperator.java
@@ -20,6 +20,8 @@ package com.huawei.boostkit.hive;
 
 import static com.huawei.boostkit.hive.expression.TypeUtils.buildInputDataType;
 import static nova.hetu.omniruntime.constants.FunctionType.OMNI_AGGREGATION_TYPE_COUNT_ALL;
+import static nova.hetu.omniruntime.type.DataType.DataTypeId.OMNI_CHAR;
+import static nova.hetu.omniruntime.type.DataType.DataTypeId.OMNI_VARCHAR;
 import static org.apache.hadoop.hive.ql.exec.GroupByOperator.groupingSet2BitSet;
 import static org.apache.hadoop.hive.ql.exec.GroupByOperator.shouldEmitSummaryRow;
 
@@ -29,6 +31,8 @@ import com.huawei.boostkit.hive.expression.TypeUtils;
 import javolution.util.FastBitSet;
 import nova.hetu.omniruntime.constants.FunctionType;
 import nova.hetu.omniruntime.operator.OmniOperator;
+import nova.hetu.omniruntime.operator.OmniOperatorFactory;
+import nova.hetu.omniruntime.operator.aggregator.OmniAggregationWithExprOperatorFactory;
 import nova.hetu.omniruntime.operator.aggregator.OmniHashAggregationWithExprOperatorFactory;
 import nova.hetu.omniruntime.operator.config.OperatorConfig;
 import nova.hetu.omniruntime.operator.config.OverflowConfig;
@@ -98,7 +102,7 @@ import java.util.Set;
 public class OmniGroupByOperator extends OmniHiveOperator<OmniGroupByDesc> implements Serializable, VectorizationContextRegion, IConfigureJobConf {
     private static final long serialVersionUID = 1L;
     private static final Logger LOG = LoggerFactory.getLogger(OmniGroupByOperator.class.getName());
-    private transient OmniHashAggregationWithExprOperatorFactory omniHashAggregationWithExprOperatorFactory;
+    private transient OmniOperatorFactory omniOperatorFactory;
     private transient OmniOperator omniOperator;
     private transient List<ExprNodeEvaluator> keyFields;
     private transient boolean firstRow;
@@ -286,10 +290,16 @@ public class OmniGroupByOperator extends OmniHiveOperator<OmniGroupByDesc> imple
             groupByChanel = getExprFromExprNode(keyFields);
             aggChannels = getTwoDimenExprFromExprNode(aggChannelFields);
         }
-        omniHashAggregationWithExprOperatorFactory = new OmniHashAggregationWithExprOperatorFactory(groupByChanel, aggChannels,
-                aggChannelsFilter, sourceTypes, aggFunctionTypes, aggOutputTypes, isInputRaws, isOutputPartials,
-                operatorConfig);
-        omniOperator = omniHashAggregationWithExprOperatorFactory.createOperator();
+        if (numKeys == 0) {
+            omniOperatorFactory = new OmniAggregationWithExprOperatorFactory(groupByChanel, aggChannels,
+                    aggChannelsFilter, sourceTypes, aggFunctionTypes, aggOutputTypes, isInputRaws, isOutputPartials,
+                    operatorConfig);
+        } else {
+            omniOperatorFactory = new OmniHashAggregationWithExprOperatorFactory(groupByChanel, aggChannels,
+                    aggChannelsFilter, sourceTypes, aggFunctionTypes, aggOutputTypes, isInputRaws, isOutputPartials,
+                    operatorConfig);
+        }
+        omniOperator = omniOperatorFactory.createOperator();
     }
 
     @Override
@@ -475,14 +485,13 @@ public class OmniGroupByOperator extends OmniHiveOperator<OmniGroupByDesc> imple
         int rowCount = vec.getSize();
         int groupingSetSize = groupingSets.size();
         Vec newVec = VecFactory.createFlatVec(rowCount * groupingSetSize, vec.getType());
-        Vec flatVec = vec;
-        if (vec instanceof DictionaryVec) {
-            flatVec = ((DictionaryVec) vec).expandDictionary();
-        }
+        Vec flatVec = (vec instanceof DictionaryVec) ? ((DictionaryVec) vec).expandDictionary() : vec;
+        byte[] rawValueNulls = vec.getRawValueNulls();
+        DataType.DataTypeId dataTypeId = vec.getType().getId();
+        int[] rawValueOffset = (dataTypeId == OMNI_VARCHAR || dataTypeId == OMNI_CHAR) ? ((VarcharVec) flatVec).getRawValueOffset() : new int[0];
         for (int i = 0; i < groupingSetSize; i++) {
+            newVec.setNulls(i * rowCount, rawValueNulls, 0, rowCount);
             if ((groupingSets.get(i) & mask) == 0) {
-                DataType.DataTypeId dataTypeId = vec.getType().getId();
-                newVec.setNulls(i * rowCount, vec.getValuesNulls(0, rowCount), 0, rowCount);
                 switch (dataTypeId) {
                     case OMNI_INT:
                     case OMNI_DATE32:
@@ -509,14 +518,14 @@ public class OmniGroupByOperator extends OmniHiveOperator<OmniGroupByDesc> imple
                     case OMNI_VARCHAR:
                     case OMNI_CHAR:
                         ((VarcharVec) newVec).put(i * rowCount, ((VarcharVec) flatVec).get(0, rowCount), 0,
-                                ((VarcharVec) flatVec).getValueOffset(0, rowCount), 0, rowCount);
+                                rawValueOffset, 0, rowCount);
                         break;
                     default:
                         throw new RuntimeException("Not support dataType, dataTypeId: " + dataTypeId);
                 }
             } else {
-                boolean[] nulls = new boolean[rowCount];
-                Arrays.fill(nulls, true);
+                byte[] nulls = new byte[rowCount];
+                Arrays.fill(nulls, (byte) 1);
                 newVec.setNulls(i * rowCount, nulls, 0, rowCount);
             }
         }
@@ -712,7 +721,7 @@ public class OmniGroupByOperator extends OmniHiveOperator<OmniGroupByDesc> imple
         for (Vec vec : constantVec) {
             vec.close();
         }
-        omniHashAggregationWithExprOperatorFactory.close();
+        omniOperatorFactory.close();
         omniOperator.close();
         super.closeOp(abort);
     }