111 lines
4.8 KiB
C++
111 lines
4.8 KiB
C++
// Licensed to the Apache Software Foundation (ASF) under one
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// or more contributor license agreements. See the NOTICE file
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// distributed with this work for additional information
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// regarding copyright ownership. The ASF licenses this file
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// to you under the Apache License, Version 2.0 (the
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// "License"); you may not use this file except in compliance
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// with the License. You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing,
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// software distributed under the License is distributed on an
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// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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// KIND, either express or implied. See the License for the
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// specific language governing permissions and limitations
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// under the License.
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// This file is copied from
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// https://github.com/ClickHouse/ClickHouse/blob/master/src/Functions/Ifnull.h
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// and modified by Doris
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#pragma once
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#include "vec/columns/column_nullable.h"
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#include "vec/data_types/get_least_supertype.h"
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#include "vec/functions/function_helpers.h"
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#include "vec/functions/function_string.h"
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#include "vec/functions/simple_function_factory.h"
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#include "vec/utils/util.hpp"
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namespace doris::vectorized {
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class FunctionIfNull : public IFunction {
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public:
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static constexpr auto name = "ifnull";
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static FunctionPtr create() { return std::make_shared<FunctionIfNull>(); }
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String get_name() const override { return name; }
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size_t get_number_of_arguments() const override { return 2; }
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bool use_default_implementation_for_constants() const override { return false; }
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// be compatible with fe code
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/*
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if (fn.functionName().equalsIgnoreCase("ifnull") || fn.functionName().equalsIgnoreCase("nvl")) {
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Preconditions.checkState(children.size() == 2);
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if (children.get(0).isNullable()) {
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return children.get(1).isNullable();
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}
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return false;
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}
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*/
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DataTypePtr get_return_type_impl(const DataTypes& arguments) const override {
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if (arguments[0]->is_nullable()) {
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return arguments[1];
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}
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return arguments[0];
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}
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bool use_default_implementation_for_nulls() const override { return false; }
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// ifnull(col_left, col_right) == if(isnull(col_left), col_right, col_left)
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Status execute_impl(FunctionContext* context, Block& block, const ColumnNumbers& arguments,
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size_t result, size_t input_rows_count) override {
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ColumnWithTypeAndName& col_left = block.get_by_position(arguments[0]);
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if (col_left.column->only_null()) {
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block.get_by_position(result).column = block.get_by_position(arguments[1]).column;
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return Status::OK();
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}
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ColumnWithTypeAndName null_column_arg0 {nullptr, std::make_shared<DataTypeUInt8>(), ""};
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ColumnWithTypeAndName nested_column_arg0 {nullptr, col_left.type, ""};
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col_left.column = col_left.column->convert_to_full_column_if_const();
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/// implement isnull(col_left) logic
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if (auto* nullable = check_and_get_column<ColumnNullable>(*col_left.column)) {
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null_column_arg0.column = nullable->get_null_map_column_ptr();
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nested_column_arg0.column = nullable->get_nested_column_ptr();
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nested_column_arg0.type =
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reinterpret_cast<const DataTypeNullable*>(nested_column_arg0.type.get())
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->get_nested_type();
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} else {
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block.get_by_position(result).column = col_left.column;
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return Status::OK();
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}
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const ColumnsWithTypeAndName if_columns {
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null_column_arg0, block.get_by_position(arguments[1]), nested_column_arg0};
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// see get_return_type_impl
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// if result is nullable, means both then and else column are nullable, we use original col_left to keep nullable info
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// if result is not nullable, means both then and else column are not nullable, we use nested_column_arg0 to remove nullable info
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bool result_nullable = block.get_by_position(result).type->is_nullable();
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Block temporary_block({
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null_column_arg0,
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block.get_by_position(arguments[1]),
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result_nullable
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? col_left
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: nested_column_arg0, // if result is nullable, we need pass the original col_left else pass nested_column_arg0
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block.get_by_position(result),
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});
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auto func_if = SimpleFunctionFactory::instance().get_function(
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"if", if_columns, block.get_by_position(result).type);
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func_if->execute(context, temporary_block, {0, 1, 2}, 3, input_rows_count);
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block.get_by_position(result).column = temporary_block.get_by_position(3).column;
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return Status::OK();
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}
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};
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} // namespace doris::vectorized
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