| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| **/ |
| |
| #ifndef QUICKSTEP_EXPRESSIONS_AGGREGATION_AGGREGATE_FUNCTION_COUNT_HPP_ |
| #define QUICKSTEP_EXPRESSIONS_AGGREGATION_AGGREGATE_FUNCTION_COUNT_HPP_ |
| |
| #include <string> |
| #include <vector> |
| |
| #include "expressions/aggregation/AggregateFunction.hpp" |
| #include "expressions/aggregation/AggregationID.hpp" |
| #include "utility/Macros.hpp" |
| |
| namespace quickstep { |
| |
| class AggregationHandle; |
| class Type; |
| |
| /** \addtogroup Expressions |
| * @{ |
| */ |
| |
| /** |
| * @brief AggregateFunction representing SQL COUNT. |
| **/ |
| class AggregateFunctionCount : public AggregateFunction { |
| public: |
| static const AggregateFunctionCount& Instance() { |
| static AggregateFunctionCount instance; |
| return instance; |
| } |
| |
| std::string getName() const override { |
| return "COUNT"; |
| } |
| |
| bool canApplyToTypes( |
| const std::vector<const Type*> &argument_types) const override; |
| |
| const Type* resultTypeForArgumentTypes( |
| const std::vector<const Type*> &argument_types) const override; |
| |
| AggregationHandle* createHandle( |
| const std::vector<const Type*> &argument_types) const override; |
| |
| private: |
| AggregateFunctionCount() |
| : AggregateFunction(AggregationID::kCount) { |
| } |
| |
| DISALLOW_COPY_AND_ASSIGN(AggregateFunctionCount); |
| }; |
| |
| /** @} */ |
| |
| } // namespace quickstep |
| |
| #endif // QUICKSTEP_EXPRESSIONS_AGGREGATION_AGGREGATE_FUNCTION_COUNT_HPP_ |