#pragma once #include namespace DB { class ColumnNothing final : public COWHelper { private: friend class COWHelper; ColumnNothing(size_t s_) { s = s_; } ColumnNothing(const ColumnNothing &) = default; public: const char * getFamilyName() const override { return "Nothing"; } MutableColumnPtr cloneDummy(size_t s_) const override { return ColumnNothing::create(s_); } bool canBeInsideNullable() const override { return true; } bool structureEquals(const IColumn & rhs) const override { return typeid(rhs) == typeid(ColumnNothing); } }; }