ClickHouse/dbms/src/AggregateFunctions/AggregateFunctionNothing.h
2019-02-11 22:26:32 +03:00

79 lines
1.7 KiB
C++

#pragma once
#include <DataTypes/DataTypeNullable.h>
#include <DataTypes/DataTypeNothing.h>
#include <Columns/IColumn.h>
#include <AggregateFunctions/IAggregateFunction.h>
namespace DB
{
/** Aggregate function that takes arbitrary number of arbitrary arguments and does nothing.
*/
class AggregateFunctionNothing final : public IAggregateFunctionHelper<AggregateFunctionNothing>
{
public:
AggregateFunctionNothing(const DataTypes & arguments, const Array & params)
: IAggregateFunctionHelper<AggregateFunctionNothing>(arguments, params) {}
String getName() const override
{
return "nothing";
}
DataTypePtr getReturnType() const override
{
return std::make_shared<DataTypeNullable>(std::make_shared<DataTypeNothing>());
}
void create(AggregateDataPtr) const override
{
}
void destroy(AggregateDataPtr) const noexcept override
{
}
bool hasTrivialDestructor() const override
{
return true;
}
size_t sizeOfData() const override
{
return 0;
}
size_t alignOfData() const override
{
return 1;
}
void add(AggregateDataPtr, const IColumn **, size_t, Arena *) const override
{
}
void merge(AggregateDataPtr, ConstAggregateDataPtr, Arena *) const override
{
}
void serialize(ConstAggregateDataPtr, WriteBuffer &) const override
{
}
void deserialize(AggregateDataPtr, ReadBuffer &, Arena *) const override
{
}
void insertResultInto(ConstAggregateDataPtr, IColumn & to) const override
{
to.insertDefault();
}
const char * getHeaderFilePath() const override { return __FILE__; }
};
}