ClickHouse/src/Functions/FunctionDateOrDateTimeToDateTimeOrDateTime64.h
Robert Schulze 72b9d75a84
Add compat setting for non-const timezones
SQL function toTimezone() converts a Date or DateTime into another
timezone. The problem is that the timezone is part of the Date /
DateTime type but not part of the internal representation (value). This
led to the fact that toTimeZone() wqith non-const timezones produced
wrong and misleading results until #48471 (shipped with v23.4) enforced
a const timezone.

Unfortunately, this PR also broke existing table definitions with
non-const timezones, e.g. in ALIAS expressions. So while #48471
addressed the issue appropriately, it is really backwards-incompatible.

This PR adds a setting to toggle the behavior and makes it also part of
the compatibility profile.
2023-06-10 16:56:42 +00:00

94 lines
4.0 KiB
C++

#pragma once
#include <Functions/IFunctionDateOrDateTime.h>
namespace DB
{
namespace ErrorCodes
{
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
}
template <typename Transform>
class FunctionDateOrDateTimeToDateTimeOrDateTime64 : public IFunctionDateOrDateTime<Transform>
{
private:
const bool enable_extended_results_for_datetime_functions = false;
public:
static FunctionPtr create(ContextPtr context_)
{
return std::make_shared<FunctionDateOrDateTimeToDateTimeOrDateTime64>(context_);
}
explicit FunctionDateOrDateTimeToDateTimeOrDateTime64(ContextPtr context_)
: enable_extended_results_for_datetime_functions(context_->getSettingsRef().enable_extended_results_for_datetime_functions)
{
}
DataTypePtr getReturnTypeImpl(const ColumnsWithTypeAndName & arguments) const override
{
this->checkArguments(arguments, /*is_result_type_date_or_date32*/ false);
const IDataType * from_type = arguments[0].type.get();
WhichDataType which(from_type);
std::string time_zone = extractTimeZoneNameFromFunctionArguments(arguments, 1, 0, false);
/// If the time zone is specified but empty, throw an exception.
/// only validate the time_zone part if the number of arguments is 2.
if (arguments.size() == 2 && time_zone.empty())
throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
"Function {} supports a 2nd argument (optional) that must be a valid time zone",
this->getName());
if ((which.isDate32() || which.isDateTime64()) && enable_extended_results_for_datetime_functions)
{
Int64 scale = DataTypeDateTime64::default_scale;
if (which.isDateTime64())
{
if (const auto * dt64 = checkAndGetDataType<DataTypeDateTime64>(arguments[0].type.get()))
scale = dt64->getScale();
}
return std::make_shared<DataTypeDateTime64>(scale, time_zone);
}
else
return std::make_shared<DataTypeDateTime>(time_zone);
}
ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, size_t input_rows_count) const override
{
const IDataType * from_type = arguments[0].type.get();
WhichDataType which(from_type);
if (which.isDate())
return DateTimeTransformImpl<DataTypeDate, DataTypeDateTime, Transform>::execute(arguments, result_type, input_rows_count);
else if (which.isDate32())
{
if (enable_extended_results_for_datetime_functions)
return DateTimeTransformImpl<DataTypeDate32, DataTypeDateTime64, Transform, /*is_extended_result*/ true>::execute(arguments, result_type, input_rows_count);
else
return DateTimeTransformImpl<DataTypeDate32, DataTypeDateTime, Transform>::execute(arguments, result_type, input_rows_count);
}
else if (which.isDateTime())
return DateTimeTransformImpl<DataTypeDateTime, DataTypeDateTime, Transform>::execute(arguments, result_type, input_rows_count);
else if (which.isDateTime64())
{
const auto scale = static_cast<const DataTypeDateTime64 *>(from_type)->getScale();
const TransformDateTime64<Transform> transformer(scale);
if (enable_extended_results_for_datetime_functions)
return DateTimeTransformImpl<DataTypeDateTime64, DataTypeDateTime64, decltype(transformer), /*is_extended_result*/ true>::execute(arguments, result_type, input_rows_count, transformer);
else
return DateTimeTransformImpl<DataTypeDateTime64, DataTypeDateTime, decltype(transformer)>::execute(arguments, result_type, input_rows_count, transformer);
}
else
throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
"Illegal type {} of argument of function {}",
arguments[0].type->getName(), this->getName());
}
};
}