fixed the build, added some comments

cmake/find/avro.cmake

@@ -1,3 +1,4 @@
+# Needed when using Apache Avro serialization format
 option (ENABLE_AVRO "Enable Avro" ${ENABLE_LIBRARIES})
 
 if (NOT ENABLE_AVRO)

cmake/find/ssl.cmake

@@ -1,3 +1,5 @@
+# Needed when securely connecting to an external server, e.g.
+# clickhouse-client --host ... --secure
 option(ENABLE_SSL "Enable ssl" ${ENABLE_LIBRARIES})
 
 if(NOT ENABLE_SSL)

src/AggregateFunctions/AggregateFunctionAvg.cpp

@@ -25,11 +25,20 @@ AggregateFunctionPtr createAggregateFunctionAvg(const std::string & name, const
     assertNoParameters(name, parameters);
     assertUnary(name, argument_types);
 
-    if (!allowType(argument_types[0]))
-        throw Exception("Illegal type " + argument_types[0]->getName() + " of argument for aggregate function " + name,
+    const DataTypePtr& data_type = argument_types[0];
+
+    if (!allowType(data_type))
+        throw Exception("Illegal type " + data_type->getName() + " of argument for aggregate function " + name,
             ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
 
-    return std::make_shared<AggregateFunctionAvg>(argument_types);
+    AggregateFunctionPtr res;
+
+    if (isDecimal(data_type))
+        res.reset(createWithDecimalType<AggregateFunctionAvg>(*data_type, argument_types));
+    else
+        res.reset(createWithNumericType<AggregateFunctionAvg>(*data_type, argument_types));
+
+    return res;
 }
 }
 

src/AggregateFunctions/AggregateFunctionAvg.h

@@ -21,6 +21,13 @@ struct RationalFraction
     Float64 NO_SANITIZE_UNDEFINED result() const { return numerator / denominator; }
 };
 
+template <class T> constexpr bool DecimalOrExtendedInt =
+    IsDecimalNumber<T>
+    || std::is_same_v<T, Int128>
+    || std::is_same_v<T, Int256>
+    || std::is_same_v<T, UInt128>
+    || std::is_same_v<T, UInt256>;
+
 /**
  * The discussion showed that the easiest (and simplest) way is to cast both the columns of numerator and denominator
  * to Float64. Another way would be to write some template magic that figures out the appropriate numerator
@@ -78,14 +85,22 @@ public:
     }
 };
 
-class AggregateFunctionAvg final : public AggregateFunctionAvgBase<UInt64, AggregateFunctionAvg>
+template <class T>
+class AggregateFunctionAvg final : public AggregateFunctionAvgBase<UInt64, AggregateFunctionAvg<T>>
 {
 public:
-    using AggregateFunctionAvgBase<UInt64, AggregateFunctionAvg>::AggregateFunctionAvgBase;
+    using AggregateFunctionAvgBase<UInt64, AggregateFunctionAvg<T>>::AggregateFunctionAvgBase;
 
     void add(AggregateDataPtr place, const IColumn ** columns, size_t row_num, Arena *) const final
     {
-        this->data(place).numerator += columns[0]->getFloat64(row_num);
+        if constexpr(IsDecimalNumber<T>)
+            this->data(place).numerator += columns[0]->getFloat64(row_num);
+        else if constexpr(DecimalOrExtendedInt<T>)
+            this->data(place).numerator += static_cast<Float64>(
+                static_cast<const ColumnVector<T> &>(*columns[0]).getData()[row_num]);
+        else
+            this->data(place).numerator += static_cast<const ColumnVector<T> &>(*columns[0]).getData()[row_num];
+
         ++this->data(place).denominator;
     }
 

src/AggregateFunctions/AggregateFunctionAvgWeighted.cpp

@@ -27,6 +27,39 @@ bool allowTypes(const DataTypePtr& left, const DataTypePtr& right) noexcept
     return allow(l_dt) && allow(r_dt);
 }
 
+#define AT_SWITCH(LINE) \
+    switch (which.idx) \
+    { \
+        LINE(Int8); LINE(Int16); LINE(Int32); LINE(Int64); LINE(Int128); LINE(Int256); \
+        LINE(UInt8); LINE(UInt16); LINE(UInt32); LINE(UInt64); LINE(UInt128); LINE(UInt256); \
+        LINE(Decimal32); LINE(Decimal64); LINE(Decimal128); LINE(Decimal256); \
+        LINE(Float32); LINE(Float64); \
+        default: return nullptr; \
+    }
+
+template <class First, class ... TArgs>
+static IAggregateFunction * create(const IDataType & second_type, TArgs && ... args)
+{
+    const WhichDataType which(second_type);
+
+#define LINE(Type) \
+    case TypeIndex::Type:       return new AggregateFunctionAvgWeighted<First, Type>(std::forward<TArgs>(args)...)
+    AT_SWITCH(LINE)
+#undef LINE
+}
+
+// Not using helper functions because there are no templates for binary decimal/numeric function.
+template <class... TArgs>
+static IAggregateFunction * create(const IDataType & first_type, const IDataType & second_type, TArgs && ... args)
+{
+    const WhichDataType which(first_type);
+
+#define LINE(Type) \
+    case TypeIndex::Type:       return create<Type, TArgs...>(second_type, std::forward<TArgs>(args)...)
+    AT_SWITCH(LINE)
+#undef LINE
+}
+
 AggregateFunctionPtr createAggregateFunctionAvgWeighted(const std::string & name, const DataTypes & argument_types, const Array & parameters)
 {
     assertNoParameters(name, parameters);
@@ -42,7 +75,9 @@ AggregateFunctionPtr createAggregateFunctionAvgWeighted(const std::string & name
             " are non-conforming as arguments for aggregate function " + name,
             ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
 
-    return std::make_shared<AggregateFunctionAvgWeighted>(argument_types);
+    AggregateFunctionPtr ptr;
+    ptr.reset(create(*data_type, *data_type_weight, argument_types));
+    return ptr;
 }
 }
 

src/AggregateFunctions/AggregateFunctionAvgWeighted.h

@@ -5,17 +5,34 @@
 
 namespace DB
 {
-class AggregateFunctionAvgWeighted final : public AggregateFunctionAvgBase<Float64, AggregateFunctionAvgWeighted>
+template <class Value, class Weight>
+class AggregateFunctionAvgWeighted final :
+    public AggregateFunctionAvgBase<Float64, AggregateFunctionAvgWeighted<Value, Weight>>
 {
 public:
-    using AggregateFunctionAvgBase<Float64, AggregateFunctionAvgWeighted>::AggregateFunctionAvgBase;
+    using Base = AggregateFunctionAvgBase<Float64, AggregateFunctionAvgWeighted<Value, Weight>>;
+    using Base::Base;
 
     void add(AggregateDataPtr place, const IColumn ** columns, size_t row_num, Arena *) const override
     {
-        const auto value = columns[0]->getFloat64(row_num);
-        const auto weight = columns[1]->getFloat64(row_num);
+        const Float64 value = [&columns, row_num] {
+            if constexpr(IsDecimalNumber<Value>)
+                return columns[0]->getFloat64(row_num);
+            else
+                return static_cast<Float64>(static_cast<const ColumnVector<Value>&>(*columns[0]).getData()[row_num]);
+        }();
 
-        this->data(place).numerator += value * weight;
+        using WeightRet = std::conditional_t<DecimalOrExtendedInt<Weight>, Float64, Weight>;
+        const WeightRet weight = [&columns, row_num]() -> WeightRet {
+            if constexpr(IsDecimalNumber<Weight>)
+                return columns[1]->getFloat64(row_num);
+            else if constexpr(DecimalOrExtendedInt<Weight>)
+                return static_cast<Float64>(static_cast<const ColumnVector<Weight>&>(*columns[1]).getData()[row_num]);
+            else
+                return static_cast<const ColumnVector<Weight>&>(*columns[1]).getData()[row_num];
+        }();
+
+        this->data(place).numerator += weight * value;
         this->data(place).denominator += weight;
     }