[feature](Nereids): Support variance_samp function. (#15500)

fe/fe-core/src/main/java/org/apache/doris/catalog/BuiltinAggregateFunctions.java

@@ -35,14 +35,15 @@ import org.apache.doris.nereids.trees.expressions.functions.agg.Min;
 import org.apache.doris.nereids.trees.expressions.functions.agg.Ndv;
 import org.apache.doris.nereids.trees.expressions.functions.agg.Sum;
 import org.apache.doris.nereids.trees.expressions.functions.agg.Variance;
+import org.apache.doris.nereids.trees.expressions.functions.agg.VarianceSamp;
 
 import com.google.common.collect.ImmutableList;
 
 /**
  * Builtin aggregate functions.
- *
+ * <p>
  * Note: Please ensure that this class only has some lists and no procedural code.
- *       It helps to be clear and concise.
+ * It helps to be clear and concise.
  */
 public class BuiltinAggregateFunctions implements FunctionHelper {
     public final ImmutableList<AggregateFunc> aggregateFunctions = ImmutableList.of(
@@ -64,11 +65,13 @@ public class BuiltinAggregateFunctions implements FunctionHelper {
             agg(Min.class),
             agg(Ndv.class),
             agg(Sum.class),
-            agg(Variance.class, "variance")
+            agg(Variance.class, "variance", "variance_pop", "var_pop"),
+            agg(VarianceSamp.class, "variance_samp", "var_samp")
     );
 
     public static final BuiltinAggregateFunctions INSTANCE = new BuiltinAggregateFunctions();
 
     // Note: Do not add any code here!
-    private BuiltinAggregateFunctions() {}
+    private BuiltinAggregateFunctions() {
+    }
 }

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/agg/VarianceSamp.java

@@ -0,0 +1,86 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+package org.apache.doris.nereids.trees.expressions.functions.agg;
+
+import org.apache.doris.catalog.FunctionSignature;
+import org.apache.doris.nereids.trees.expressions.Expression;
+import org.apache.doris.nereids.trees.expressions.functions.ExplicitlyCastableSignature;
+import org.apache.doris.nereids.trees.expressions.functions.PropagateNullable;
+import org.apache.doris.nereids.trees.expressions.shape.UnaryExpression;
+import org.apache.doris.nereids.trees.expressions.visitor.ExpressionVisitor;
+import org.apache.doris.nereids.types.BigIntType;
+import org.apache.doris.nereids.types.DecimalV2Type;
+import org.apache.doris.nereids.types.DoubleType;
+import org.apache.doris.nereids.types.FloatType;
+import org.apache.doris.nereids.types.IntegerType;
+import org.apache.doris.nereids.types.LargeIntType;
+import org.apache.doris.nereids.types.SmallIntType;
+import org.apache.doris.nereids.types.TinyIntType;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableList;
+
+import java.util.List;
+
+/**
+ * VarianceSamp function
+ */
+public class VarianceSamp extends AggregateFunction implements UnaryExpression, PropagateNullable,
+        ExplicitlyCastableSignature {
+
+    public static final List<FunctionSignature> SIGNATURES = ImmutableList.of(
+            FunctionSignature.ret(DoubleType.INSTANCE).args(DoubleType.INSTANCE),
+            FunctionSignature.ret(DoubleType.INSTANCE).args(FloatType.INSTANCE),
+            FunctionSignature.ret(DoubleType.INSTANCE).args(LargeIntType.INSTANCE),
+            FunctionSignature.ret(DoubleType.INSTANCE).args(BigIntType.INSTANCE),
+            FunctionSignature.ret(DoubleType.INSTANCE).args(SmallIntType.INSTANCE),
+            FunctionSignature.ret(DoubleType.INSTANCE).args(IntegerType.INSTANCE),
+            FunctionSignature.ret(DoubleType.INSTANCE).args(TinyIntType.INSTANCE),
+            FunctionSignature.ret(DecimalV2Type.SYSTEM_DEFAULT).args(DecimalV2Type.SYSTEM_DEFAULT)
+    );
+
+    public VarianceSamp(Expression child) {
+        super("variance_samp", child);
+    }
+
+    public VarianceSamp(boolean isDistinct, Expression child) {
+        super("variance_samp", isDistinct, child);
+    }
+
+    @Override
+    public List<FunctionSignature> getSignatures() {
+        return SIGNATURES;
+    }
+
+    @Override
+    public AggregateFunction withChildren(List<Expression> children) {
+        Preconditions.checkArgument(children.size() == 1);
+        return new VarianceSamp(isDistinct, children.get(0));
+    }
+
+    @Override
+    public AggregateFunction withDistinctAndChildren(boolean isDistinct, List<Expression> children) {
+        Preconditions.checkArgument(children.size() == 1);
+        return new VarianceSamp(isDistinct, children.get(0));
+    }
+
+    @Override
+    public <R, C> R accept(ExpressionVisitor<R, C> visitor, C context) {
+        return visitor.visitVarianceSamp(this, context);
+    }
+}

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/visitor/AggregateFunctionVisitor.java

@@ -34,8 +34,11 @@ import org.apache.doris.nereids.trees.expressions.functions.agg.MultiDistinctSum
 import org.apache.doris.nereids.trees.expressions.functions.agg.Ndv;
 import org.apache.doris.nereids.trees.expressions.functions.agg.Sum;
 import org.apache.doris.nereids.trees.expressions.functions.agg.Variance;
+import org.apache.doris.nereids.trees.expressions.functions.agg.VarianceSamp;
 
-/** AggregateFunctionVisitor. */
+/**
+ * AggregateFunctionVisitor.
+ */
 public interface AggregateFunctionVisitor<R, C> {
     R visitAggregateFunction(AggregateFunction aggregateFunction, C context);
 
@@ -87,6 +90,10 @@ public interface AggregateFunctionVisitor<R, C> {
         return visitAggregateFunction(variance, context);
     }
 
+    default R visitVarianceSamp(VarianceSamp varianceSamp, C context) {
+        return visitAggregateFunction(varianceSamp, context);
+    }
+
     default R visitNdv(Ndv ndv, C context) {
         return visitAggregateFunction(ndv, context);
     }