#pragma once #include namespace DB { class ColumnNothing final : public COWPtrHelper { private: friend class COWPtrHelper; 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; } }; }