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328 lines
12 KiB
C++
328 lines
12 KiB
C++
#include <sstream>
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#include <Common/typeid_cast.h>
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#include <DataTypes/getLeastCommonType.h>
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#include <DataTypes/DataTypeArray.h>
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#include <DataTypes/DataTypeTuple.h>
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#include <DataTypes/DataTypeNullable.h>
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#include <DataTypes/DataTypeNothing.h>
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#include <DataTypes/DataTypeString.h>
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#include <DataTypes/DataTypeFixedString.h>
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#include <DataTypes/DataTypeDate.h>
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#include <DataTypes/DataTypeDateTime.h>
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#include <DataTypes/DataTypesNumber.h>
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namespace DB
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{
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namespace ErrorCodes
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{
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extern const int BAD_ARGUMENTS;
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extern const int NO_COMMON_TYPE;
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}
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namespace
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{
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String getExceptionMessagePrefix(const DataTypes & types)
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{
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std::stringstream res;
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res << "There is no common type for types ";
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bool first = true;
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for (const auto & type : types)
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{
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if (!first)
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res << ", ";
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first = false;
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res << type->getName();
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}
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return res.str();
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}
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}
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DataTypePtr getLeastCommonType(const DataTypes & types)
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{
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/// Trivial cases
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if (types.empty())
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return std::make_shared<DataTypeNothing>();
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if (types.size() == 1)
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return types[0];
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/// All types are equal
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{
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bool all_equal = true;
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for (size_t i = 1, size = types.size(); i < size; ++i)
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{
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if (!types[i]->equals(*types[0]))
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{
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all_equal = false;
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break;
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}
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}
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if (all_equal)
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return types[0];
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}
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/// Recursive rules
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/// For Arrays
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{
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bool have_array = false;
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bool all_arrays = true;
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DataTypes nested_types;
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nested_types.reserve(types.size());
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for (const auto & type : types)
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{
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if (const DataTypeArray * type_array = typeid_cast<const DataTypeArray *>(type.get()))
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{
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have_array = true;
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nested_types.emplace_back(type_array->getNestedType());
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}
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else
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all_arrays = false;
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}
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if (have_array)
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{
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if (!all_arrays)
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throw Exception(getExceptionMessagePrefix(types) + " because some of them are Array and some of them are not", ErrorCodes::NO_COMMON_TYPE);
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return std::make_shared<DataTypeArray>(getLeastCommonType(nested_types));
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}
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}
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/// For tuples
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{
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bool have_tuple = false;
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bool all_tuples = true;
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size_t tuple_size = 0;
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std::vector<DataTypes> nested_types;
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for (const auto & type : types)
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{
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if (const DataTypeTuple * type_tuple = typeid_cast<const DataTypeTuple *>(type.get()))
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{
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if (!have_tuple)
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{
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tuple_size = type_tuple->getElements().size();
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nested_types.resize(tuple_size);
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for (size_t elem_idx = 0; elem_idx < tuple_size; ++elem_idx)
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nested_types[elem_idx].reserve(types.size());
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}
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else if (tuple_size != type_tuple->getElements().size())
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throw Exception(getExceptionMessagePrefix(types) + " because Tuples have different sizes", ErrorCodes::NO_COMMON_TYPE);
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have_tuple = true;
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for (size_t elem_idx = 0; elem_idx < tuple_size; ++elem_idx)
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nested_types[elem_idx].emplace_back(type_tuple->getElements()[elem_idx]);
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}
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else
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all_tuples = false;
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if (have_tuple)
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{
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if (!all_tuples)
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throw Exception(getExceptionMessagePrefix(types) + " because some of them are Tuple and some of them are not", ErrorCodes::NO_COMMON_TYPE);
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DataTypes common_tuple_types(tuple_size);
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for (size_t elem_idx = 0; elem_idx < tuple_size; ++elem_idx)
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common_tuple_types[elem_idx] = getLeastCommonType(nested_types[elem_idx]);
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return std::make_shared<DataTypeTuple>(common_tuple_types);
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}
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}
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}
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/// For Nullable
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{
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bool have_nullable = false;
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DataTypes nested_types;
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nested_types.reserve(types.size());
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for (const auto & type : types)
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{
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if (const DataTypeNullable * type_nullable = typeid_cast<const DataTypeNullable *>(type.get()))
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{
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have_nullable = true;
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if (!type_nullable->isNull())
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nested_types.emplace_back(type_nullable->getNestedType());
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}
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else
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nested_types.emplace_back(type);
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}
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if (have_nullable)
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{
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return std::make_shared<DataTypeNullable>(getLeastCommonType(nested_types));
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}
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}
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/// Non-recursive rules
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/// For String and FixedString, or for different FixedStrings, the common type is String.
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/// No other types are compatible with Strings.
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{
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bool have_string = false;
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bool all_strings = true;
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for (const auto & type : types)
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{
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if (typeid_cast<const DataTypeString *>(type.get())
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|| typeid_cast<const DataTypeFixedString *>(type.get()))
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have_string = true;
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else
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all_strings = false;
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}
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if (have_string)
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{
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if (!all_strings)
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throw Exception(getExceptionMessagePrefix(types) + " because some of them are String/FixedString and some of them are not", ErrorCodes::NO_COMMON_TYPE);
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return std::make_shared<DataTypeString>();
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}
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}
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/// For Date and DateTime, the common type is DateTime. No other types are compatible.
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{
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bool have_date_or_datetime = false;
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bool all_date_or_datetime = true;
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for (const auto & type : types)
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{
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if (typeid_cast<const DataTypeDate *>(type.get())
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|| typeid_cast<const DataTypeDateTime *>(type.get()))
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have_date_or_datetime = true;
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else
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all_date_or_datetime = false;
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}
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if (have_date_or_datetime)
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{
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if (!all_date_or_datetime)
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throw Exception(getExceptionMessagePrefix(types) + " because some of them are Date/DateTime and some of them are not", ErrorCodes::NO_COMMON_TYPE);
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return std::make_shared<DataTypeDateTime>();
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}
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}
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/// For numeric types, the most complicated part.
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{
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bool all_numbers = true;
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size_t max_bits_of_signed_integer = 0;
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size_t max_bits_of_unsigned_integer = 0;
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size_t max_mantissa_bits_of_floating = 0;
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auto maximize = [](size_t & what, size_t value)
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{
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if (value > what)
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what = value;
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};
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for (const auto & type : types)
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{
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if (typeid_cast<const DataTypeUInt8 *>(type.get()))
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maximize(max_bits_of_unsigned_integer, 8);
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else if (typeid_cast<const DataTypeUInt16 *>(type.get()))
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maximize(max_bits_of_unsigned_integer, 16);
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else if (typeid_cast<const DataTypeUInt32 *>(type.get()))
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maximize(max_bits_of_unsigned_integer, 32);
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else if (typeid_cast<const DataTypeUInt64 *>(type.get()))
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maximize(max_bits_of_unsigned_integer, 64);
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else if (typeid_cast<const DataTypeInt8 *>(type.get()))
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maximize(max_bits_of_signed_integer, 8);
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else if (typeid_cast<const DataTypeInt16 *>(type.get()))
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maximize(max_bits_of_signed_integer, 16);
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else if (typeid_cast<const DataTypeInt32 *>(type.get()))
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maximize(max_bits_of_signed_integer, 32);
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else if (typeid_cast<const DataTypeInt64 *>(type.get()))
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maximize(max_bits_of_signed_integer, 64);
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else if (typeid_cast<const DataTypeFloat32 *>(type.get()))
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maximize(max_mantissa_bits_of_floating, 24);
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else if (typeid_cast<const DataTypeFloat64 *>(type.get()))
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maximize(max_mantissa_bits_of_floating, 53);
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else
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all_numbers = false;
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}
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if (max_bits_of_signed_integer || max_bits_of_unsigned_integer || max_mantissa_bits_of_floating)
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{
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if (!all_numbers)
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throw Exception(getExceptionMessagePrefix(types) + " because some of them are numbers and some of them are not", ErrorCodes::NO_COMMON_TYPE);
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/// If there are signed and unsigned types of same bit-width, the result must be signed number with at least one more bit.
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/// Example, common of Int32, UInt32 = Int64.
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size_t min_bit_width_of_integer = std::max(max_bits_of_signed_integer, max_bits_of_unsigned_integer);
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if (max_bits_of_signed_integer == max_bits_of_unsigned_integer)
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++min_bit_width_of_integer;
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/// If the result must be floating.
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if (max_mantissa_bits_of_floating)
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{
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size_t min_mantissa_bits = std::max(min_bit_width_of_integer, max_mantissa_bits_of_floating);
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if (min_mantissa_bits <= 24)
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return std::make_shared<DataTypeFloat32>();
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else if (min_mantissa_bits <= 53)
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return std::make_shared<DataTypeFloat64>();
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else
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throw Exception(getExceptionMessagePrefix(types)
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+ " because some of them are integers and some are floating point,"
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" but there is no floating point type, that can exactly represent all required integers", ErrorCodes::NO_COMMON_TYPE);
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}
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/// If the result must be signed integer.
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if (max_bits_of_signed_integer)
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{
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if (min_bit_width_of_integer <= 8)
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return std::make_shared<DataTypeInt8>();
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else if (min_bit_width_of_integer <= 16)
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return std::make_shared<DataTypeInt16>();
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else if (min_bit_width_of_integer <= 32)
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return std::make_shared<DataTypeInt32>();
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else if (min_bit_width_of_integer <= 64)
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return std::make_shared<DataTypeInt64>();
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else
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throw Exception(getExceptionMessagePrefix(types)
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+ " because some of them are signed integers and some are unsigned integers,"
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" but there is no signed integer type, that can exactly represent all required unsigned integer values", ErrorCodes::NO_COMMON_TYPE);
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}
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/// All unsigned.
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{
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if (min_bit_width_of_integer <= 8)
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return std::make_shared<DataTypeUInt8>();
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else if (min_bit_width_of_integer <= 16)
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return std::make_shared<DataTypeUInt16>();
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else if (min_bit_width_of_integer <= 32)
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return std::make_shared<DataTypeUInt32>();
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else if (min_bit_width_of_integer <= 64)
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return std::make_shared<DataTypeUInt64>();
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else
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throw Exception("Logical error: " + getExceptionMessagePrefix(types)
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+ " but as all data types are unsigned integers, we must have found maximum unsigned integer type", ErrorCodes::NO_COMMON_TYPE);
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}
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}
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}
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/// All other data types (UUID, AggregateFunction, Enum...) are compatible only if they are the same (checked in trivial cases).
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throw Exception(getExceptionMessagePrefix(types), ErrorCodes::NO_COMMON_TYPE);
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}
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}
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