ClickHouse/dbms/src/Functions/ignore.cpp

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#include <Functions/IFunction.h>
#include <Functions/FunctionFactory.h>
#include <DataTypes/DataTypesNumber.h>
namespace DB
{
/** ignore(...) is a function that takes any arguments, and always returns 0.
*/
class FunctionIgnore : public IFunction
{
public:
static constexpr auto name = "ignore";
static FunctionPtr create(const Context &)
{
return std::make_shared<FunctionIgnore>();
}
bool isVariadic() const override
{
return true;
}
size_t getNumberOfArguments() const override
{
return 0;
}
bool useDefaultImplementationForNulls() const override { return false; }
String getName() const override
{
return name;
}
DataTypePtr getReturnTypeImpl(const DataTypes & /*arguments*/) const override
{
return std::make_shared<DataTypeUInt8>();
}
void executeImpl(Block & block, const ColumnNumbers &, size_t result, size_t input_rows_count) override
{
block.getByPosition(result).column = DataTypeUInt8().createColumnConst(input_rows_count, 0u);
}
};
void registerFunctionIgnore(FunctionFactory & factory)
{
factory.registerFunction<FunctionIgnore>();
}
}