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108 lines
3.0 KiB
C++
108 lines
3.0 KiB
C++
#pragma once
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#include <DB/DataTypes/DataTypesNumberFixed.h>
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#include <DB/AggregateFunctions/IAggregateFunction.h>
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namespace DB
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{
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/** Не агрегатная функция, а адаптер агрегатных функций,
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* который любую агрегатную функцию agg(x) делает агрегатной функцией вида aggIf(x, cond).
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* Адаптированная агрегатная функция принимает два аргумента - значение и условие,
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* и вычисляет вложенную агрегатную функцию для значений при выполненном условии.
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* Например, avgIf(x, cond) вычисляет среднее x при условии cond.
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*/
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class AggregateFunctionIf final : public IAggregateFunction
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{
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private:
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AggregateFunctionPtr nested_func_owner;
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IAggregateFunction * nested_func;
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int num_agruments;
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public:
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AggregateFunctionIf(AggregateFunctionPtr nested_) : nested_func_owner(nested_), nested_func(nested_func_owner.get()) {}
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String getName() const override
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{
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return nested_func->getName() + "If";
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}
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DataTypePtr getReturnType() const override
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{
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return nested_func->getReturnType();
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}
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void setArguments(const DataTypes & arguments) override
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{
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num_agruments = arguments.size();
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if (!typeid_cast<const DataTypeUInt8 *>(&*arguments[num_agruments - 1]))
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throw Exception("Illegal type " + arguments[num_agruments - 1]->getName() + " of second argument for aggregate function " + getName() + ". Must be UInt8.",
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ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
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DataTypes nested_arguments;
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for (int i = 0; i < num_agruments - 1; i ++)
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nested_arguments.push_back(arguments[i]);
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nested_func->setArguments(nested_arguments);
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}
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void setParameters(const Array & params) override
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{
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nested_func->setParameters(params);
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}
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void create(AggregateDataPtr place) const override
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{
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nested_func->create(place);
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}
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void destroy(AggregateDataPtr place) const noexcept override
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{
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nested_func->destroy(place);
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}
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bool hasTrivialDestructor() const override
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{
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return nested_func->hasTrivialDestructor();
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}
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size_t sizeOfData() const override
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{
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return nested_func->sizeOfData();
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}
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size_t alignOfData() const override
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{
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return nested_func->alignOfData();
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}
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void add(AggregateDataPtr place, const IColumn ** columns, size_t row_num) const override
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{
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if (static_cast<const ColumnUInt8 &>(*columns[num_agruments - 1]).getData()[row_num])
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nested_func->add(place, columns, row_num);
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}
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void merge(AggregateDataPtr place, ConstAggregateDataPtr rhs) const override
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{
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nested_func->merge(place, rhs);
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}
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void serialize(ConstAggregateDataPtr place, WriteBuffer & buf) const override
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{
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nested_func->serialize(place, buf);
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}
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void deserializeMerge(AggregateDataPtr place, ReadBuffer & buf) const override
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{
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nested_func->deserializeMerge(place, buf);
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}
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void insertResultInto(ConstAggregateDataPtr place, IColumn & to) const override
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{
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nested_func->insertResultInto(place, to);
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}
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};
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}
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