ClickHouse

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#include <Functions/IFunction.h>
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#include <Functions/FunctionHelpers.h>
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#include <Functions/FunctionFactory.h>
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#include <DataTypes/DataTypesNumber.h>
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#include <Core/ColumnNumbers.h>
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namespace DB
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{
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namespace
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{
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/// ifNotFinite(x, y) is equivalent to isFinite(x) ? x : y.
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class FunctionIfNotFinite : public IFunction
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{
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public:
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    static constexpr auto name = "ifNotFinite";
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    explicit FunctionIfNotFinite(ContextPtr context_) : context(context_) {}
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    static FunctionPtr create(ContextPtr context)
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    {
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        return std::make_shared<FunctionIfNotFinite>(context);
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    }
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    std::string getName() const override
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    {
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        return name;
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    }
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    size_t getNumberOfArguments() const override { return 2; }
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    bool useDefaultImplementationForNulls() const override { return false; }
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    bool useDefaultImplementationForConstants() const override { return true; }
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    bool isSuitableForShortCircuitArgumentsExecution(const DataTypesWithConstInfo & /*arguments*/) const override { return false; }
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    ColumnNumbers getArgumentsThatDontImplyNullableReturnType(size_t /*number_of_arguments*/) const override { return {0}; }
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    DataTypePtr getReturnTypeImpl(const ColumnsWithTypeAndName & arguments) const override
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    {
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        auto is_finite_type = FunctionFactory::instance().get("isFinite", context)->build({arguments[0]})->getResultType();
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        auto if_type = FunctionFactory::instance().get("if", context)->build({{nullptr, is_finite_type, ""}, arguments[0], arguments[1]})->getResultType();
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        return if_type;
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    }
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    ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, size_t input_rows_count) const override
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    {
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        ColumnsWithTypeAndName is_finite_columns{arguments[0]};
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        auto is_finite = FunctionFactory::instance().get("isFinite", context)->build(is_finite_columns);
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        auto res = is_finite->execute(is_finite_columns, is_finite->getResultType(), input_rows_count);
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        ColumnsWithTypeAndName if_columns
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        {
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            {res, is_finite->getResultType(), ""},
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            arguments[0],
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            arguments[1],
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        };
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        auto func_if = FunctionFactory::instance().get("if", context)->build(if_columns);
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        return func_if->execute(if_columns, result_type, input_rows_count);
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    }
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private:
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    ContextPtr context;
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};
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}
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REGISTER_FUNCTION(IfNotFinite)
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{
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    factory.registerFunction<FunctionIfNotFinite>();
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}
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}
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