mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-12-03 13:02:00 +00:00
105 lines
3.5 KiB
C++
105 lines
3.5 KiB
C++
#include <Functions/IFunctionImpl.h>
|
|
#include <Functions/FunctionHelpers.h>
|
|
#include <Functions/FunctionFactory.h>
|
|
#include <DataTypes/DataTypesNumber.h>
|
|
#include <DataTypes/DataTypeNullable.h>
|
|
#include <DataTypes/getLeastSupertype.h>
|
|
#include <Core/ColumnNumbers.h>
|
|
#include <Columns/ColumnNullable.h>
|
|
|
|
|
|
namespace DB
|
|
{
|
|
namespace
|
|
{
|
|
|
|
/// Implements the function ifNull which takes 2 arguments and returns
|
|
/// the value of the 1st argument if it is not null. Otherwise it returns
|
|
/// the value of the 2nd argument.
|
|
class FunctionIfNull : public IFunction
|
|
{
|
|
public:
|
|
static constexpr auto name = "ifNull";
|
|
|
|
explicit FunctionIfNull(const Context & context_) : context(context_) {}
|
|
|
|
static FunctionPtr create(const Context & context)
|
|
{
|
|
return std::make_shared<FunctionIfNull>(context);
|
|
}
|
|
|
|
std::string getName() const override
|
|
{
|
|
return name;
|
|
}
|
|
|
|
size_t getNumberOfArguments() const override { return 2; }
|
|
bool useDefaultImplementationForNulls() const override { return false; }
|
|
bool useDefaultImplementationForConstants() const override { return true; }
|
|
ColumnNumbers getArgumentsThatDontImplyNullableReturnType(size_t /*number_of_arguments*/) const override { return {0}; }
|
|
|
|
DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
|
|
{
|
|
if (arguments[0]->onlyNull())
|
|
return arguments[1];
|
|
|
|
if (!arguments[0]->isNullable())
|
|
return arguments[0];
|
|
|
|
return getLeastSupertype({removeNullable(arguments[0]), arguments[1]});
|
|
}
|
|
|
|
void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result, size_t input_rows_count) const override
|
|
{
|
|
/// Always null.
|
|
if (block[arguments[0]].type->onlyNull())
|
|
{
|
|
block[result].column = block[arguments[1]].column;
|
|
return;
|
|
}
|
|
|
|
/// Could not contain nulls, so nullIf makes no sense.
|
|
if (!block[arguments[0]].type->isNullable())
|
|
{
|
|
block[result].column = block[arguments[0]].column;
|
|
return;
|
|
}
|
|
|
|
/// ifNull(col1, col2) == if(isNotNull(col1), assumeNotNull(col1), col2)
|
|
|
|
ColumnsWithTypeAndName temp_block = block.data;
|
|
|
|
size_t is_not_null_pos = temp_block.size();
|
|
temp_block.emplace_back(ColumnWithTypeAndName{nullptr, std::make_shared<DataTypeUInt8>(), ""});
|
|
size_t assume_not_null_pos = temp_block.size();
|
|
temp_block.emplace_back(ColumnWithTypeAndName{nullptr, removeNullable(block[arguments[0]].type), ""});
|
|
|
|
auto is_not_null = FunctionFactory::instance().get("isNotNull", context)->build(
|
|
{temp_block[arguments[0]]});
|
|
|
|
auto assume_not_null = FunctionFactory::instance().get("assumeNotNull", context)->build(
|
|
{temp_block[arguments[0]]});
|
|
|
|
auto func_if = FunctionFactory::instance().get("if", context)->build(
|
|
{temp_block[is_not_null_pos], temp_block[assume_not_null_pos], temp_block[arguments[1]]}); //-V557
|
|
|
|
is_not_null->execute(temp_block, {arguments[0]}, is_not_null_pos, input_rows_count);
|
|
assume_not_null->execute(temp_block, {arguments[0]}, assume_not_null_pos, input_rows_count);
|
|
func_if->execute(temp_block, {is_not_null_pos, assume_not_null_pos, arguments[1]}, result, input_rows_count);
|
|
|
|
block[result].column = std::move(temp_block[result].column);
|
|
}
|
|
|
|
private:
|
|
const Context & context;
|
|
};
|
|
|
|
}
|
|
|
|
void registerFunctionIfNull(FunctionFactory & factory)
|
|
{
|
|
factory.registerFunction<FunctionIfNull>(FunctionFactory::CaseInsensitive);
|
|
}
|
|
|
|
}
|