#include #include #include #include #include namespace DB { namespace { class FunctionCurrentDatabase : public IFunction { const String db_name; public: static constexpr auto name = "currentDatabase"; static FunctionPtr create(ContextPtr context) { return std::make_shared(context->getCurrentDatabase()); } explicit FunctionCurrentDatabase(const String & db_name_) : db_name{db_name_} { } String getName() const override { return name; } size_t getNumberOfArguments() const override { return 0; } DataTypePtr getReturnTypeImpl(const DataTypes & /*arguments*/) const override { return std::make_shared(); } bool isDeterministic() const override { return false; } ColumnPtr executeImpl(const ColumnsWithTypeAndName &, const DataTypePtr &, size_t input_rows_count) const override { return DataTypeString().createColumnConst(input_rows_count, db_name); } }; } void registerFunctionCurrentDatabase(FunctionFactory & factory) { factory.registerFunction(); factory.registerFunction("DATABASE", FunctionFactory::CaseInsensitive); } }