#include #include #include namespace DB { namespace { /** ignore(...) is a function that takes any arguments, and always returns 0. */ class FunctionIgnore : public IFunction { public: static constexpr auto name = "ignore"; static FunctionPtr create(ContextPtr) { return std::make_shared(); } bool isVariadic() const override { return true; } size_t getNumberOfArguments() const override { return 0; } bool useDefaultImplementationForNulls() const override { return false; } bool isSuitableForConstantFolding() const override { return false; } bool isSuitableForShortCircuitArgumentsExecution(const DataTypesWithConstInfo & /*arguments*/) const override { return false; } /// We should never return LowCardinality result, cause we declare that result is always constant zero. /// (in getResultIfAlwaysReturnsConstantAndHasArguments) bool useDefaultImplementationForLowCardinalityColumns() const override { return false; } bool useDefaultImplementationForSparseColumns() const override { return false; } String getName() const override { return name; } DataTypePtr getReturnTypeImpl(const DataTypes & /*arguments*/) const override { return std::make_shared(); } ColumnPtr executeImpl(const ColumnsWithTypeAndName &, const DataTypePtr &, size_t input_rows_count) const override { return DataTypeUInt8().createColumnConst(input_rows_count, 0u); } }; } void registerFunctionIgnore(FunctionFactory & factory) { factory.registerFunction(); } }