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75 lines
2.3 KiB
C++
75 lines
2.3 KiB
C++
#pragma once
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#include <DB/AggregateFunctions/AggregateFunctionsMinMaxAny.h>
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#include <DB/AggregateFunctions/IBinaryAggregateFunction.h>
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namespace DB
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{
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/// Возможные значения параметров шаблонов см. в AggregateFunctionsMinMaxAny.h
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template <typename ResultData, typename ValueData>
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struct AggregateFunctionsArgMinMaxData
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{
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using ResultData_t = ResultData;
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using ValueData_t = ValueData;
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ResultData result; // аргумент, при котором достигается минимальное/максимальное значение value.
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ValueData value; // значение, для которого считается минимум/максимум.
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};
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/// Возвращает первое попавшееся значение arg для минимального/максимального value. Пример: argMax(arg, value).
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template <typename Data>
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class AggregateFunctionsArgMinMax final : public IBinaryAggregateFunction<Data, AggregateFunctionsArgMinMax<Data>>
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{
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private:
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DataTypePtr type_res;
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DataTypePtr type_val;
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public:
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String getName() const override { return (0 == strcmp(Data::ValueData_t::name(), "min")) ? "argMin" : "argMax"; }
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DataTypePtr getReturnType() const override
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{
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return type_res;
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}
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void setArgumentsImpl(const DataTypes & arguments)
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{
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type_res = arguments[0];
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type_val = arguments[1];
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}
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void addImpl(AggregateDataPtr place, const IColumn & column_arg, const IColumn & column_max, size_t row_num) const
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{
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if (this->data(place).value.changeIfBetter(column_max, row_num))
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this->data(place).result.change(column_arg, 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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if (this->data(place).value.changeIfBetter(this->data(rhs).value))
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this->data(place).result.change(this->data(rhs).result);
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}
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void serialize(ConstAggregateDataPtr place, WriteBuffer & buf) const override
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{
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this->data(place).result.write(buf, *type_res.get());
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this->data(place).value.write(buf, *type_val.get());
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}
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void deserialize(AggregateDataPtr place, ReadBuffer & buf) const override
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{
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this->data(place).result.read(buf, *type_res.get());
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this->data(place).value.read(buf, *type_val.get());
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}
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void insertResultInto(ConstAggregateDataPtr place, IColumn & to) const override
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{
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this->data(place).result.insertResultInto(to);
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}
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};
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}
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