ClickHouse/dbms/src/Functions/isNotNull.cpp

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#include <Functions/IFunction.h>
#include <Functions/FunctionHelpers.h>
#include <Functions/FunctionFactory.h>
#include <DataTypes/DataTypesNumber.h>
#include <Core/ColumnNumbers.h>
#include <Columns/ColumnNullable.h>
namespace DB
{
/// Implements the function isNotNull which returns true if a value
/// is not null, false otherwise.
class FunctionIsNotNull : public IFunction
{
public:
static constexpr auto name = "isNotNull";
static FunctionPtr create(const Context &)
{
return std::make_shared<FunctionIsNotNull>();
}
std::string getName() const override
{
return name;
}
size_t getNumberOfArguments() const override { return 1; }
bool useDefaultImplementationForNulls() const override { return false; }
bool useDefaultImplementationForConstants() const override { return true; }
DataTypePtr getReturnTypeImpl(const DataTypes &) const override
{
return std::make_shared<DataTypeUInt8>();
}
void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result, size_t input_rows_count) override
{
const ColumnWithTypeAndName & elem = block.getByPosition(arguments[0]);
if (elem.column->isColumnNullable())
{
/// Return the negated null map.
auto res_column = ColumnUInt8::create(input_rows_count);
const auto & src_data = static_cast<const ColumnNullable &>(*elem.column).getNullMapData();
auto & res_data = static_cast<ColumnUInt8 &>(*res_column).getData();
for (size_t i = 0; i < input_rows_count; ++i)
res_data[i] = !src_data[i];
block.getByPosition(result).column = std::move(res_column);
}
else
{
/// Since no element is nullable, return a constant one.
block.getByPosition(result).column = DataTypeUInt8().createColumnConst(elem.column->size(), 1u);
}
}
};
void registerFunctionIsNotNull(FunctionFactory & factory)
{
factory.registerFunction<FunctionIsNotNull>();
}
}