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02bd35924e
Another one untuple implementation
100 lines
2.6 KiB
C++
100 lines
2.6 KiB
C++
#include <Functions/IFunctionImpl.h>
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#include <Functions/FunctionFactory.h>
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#include <DataTypes/DataTypeTuple.h>
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#include <Columns/ColumnTuple.h>
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#include <memory>
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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 NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
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}
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namespace
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{
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/** tuple(x, y, ...) is a function that allows you to group several columns
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* tupleElement(tuple, n) is a function that allows you to retrieve a column from tuple.
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*/
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class FunctionTuple : public IFunction
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{
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public:
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static constexpr auto name = "tuple";
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static FunctionPtr create(const Context &)
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{
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return std::make_shared<FunctionTuple>();
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}
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String getName() const override
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{
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return name;
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}
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bool isVariadic() const override
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{
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return true;
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}
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size_t getNumberOfArguments() const override
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{
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return 0;
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}
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bool isInjective(const ColumnsWithTypeAndName &) const override
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{
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return true;
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}
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bool useDefaultImplementationForNulls() const override { return false; }
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bool useDefaultImplementationForConstants() const override { return true; }
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DataTypePtr getReturnTypeImpl(const ColumnsWithTypeAndName & arguments) const override
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{
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if (arguments.empty())
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throw Exception("Function " + getName() + " requires at least one argument.", ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
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DataTypes types;
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Strings names;
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for (const auto & argument : arguments)
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{
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types.emplace_back(argument.type);
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names.emplace_back(argument.name);
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}
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/// Create named tuple if possible.
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if (DataTypeTuple::canBeCreatedWithNames(names))
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return std::make_shared<DataTypeTuple>(types, names, false);
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return std::make_shared<DataTypeTuple>(types);
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}
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ColumnPtr executeImpl(ColumnsWithTypeAndName & arguments, const DataTypePtr &, size_t /*input_rows_count*/) const override
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{
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size_t tuple_size = arguments.size();
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Columns tuple_columns(tuple_size);
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for (size_t i = 0; i < tuple_size; ++i)
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{
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/** If tuple is mixed of constant and not constant columns,
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* convert all to non-constant columns,
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* because many places in code expect all non-constant columns in non-constant tuple.
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*/
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tuple_columns[i] = arguments[i].column->convertToFullColumnIfConst();
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}
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return ColumnTuple::create(tuple_columns);
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}
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};
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}
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void registerFunctionTuple(FunctionFactory & factory)
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{
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factory.registerFunction<FunctionTuple>();
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}
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}
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