ClickHouse/src/Functions/extractTimeZoneFromFunctionArguments.cpp
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

84 lines
3.0 KiB
C++

#include <Functions/extractTimeZoneFromFunctionArguments.h>
#include <Functions/FunctionHelpers.h>
#include <Core/Block.h>
#include <DataTypes/DataTypeDateTime.h>
#include <DataTypes/DataTypeDateTime64.h>
#include <Columns/ColumnString.h>
#include <Common/DateLUT.h>
namespace DB
{
namespace ErrorCodes
{
extern const int ILLEGAL_COLUMN;
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
}
std::string extractTimeZoneNameFromColumn(const IColumn * column, const String & column_name)
{
const ColumnConst * time_zone_column = checkAndGetColumnConst<ColumnString>(column);
if (!time_zone_column)
throw Exception(ErrorCodes::ILLEGAL_COLUMN,
"Illegal column {} of time zone argument of function, must be a constant string",
column_name);
return time_zone_column->getValue<String>();
}
std::string extractTimeZoneNameFromFunctionArguments(const ColumnsWithTypeAndName & arguments, size_t time_zone_arg_num, size_t datetime_arg_num, bool allow_nonconst_timezone_arguments)
{
/// Explicit time zone may be passed in last argument.
if ((arguments.size() == time_zone_arg_num + 1)
&& (!allow_nonconst_timezone_arguments || arguments[time_zone_arg_num].column))
{
return extractTimeZoneNameFromColumn(arguments[time_zone_arg_num].column.get(), arguments[time_zone_arg_num].name);
}
else
{
if (arguments.size() <= datetime_arg_num)
return {};
const auto & dt_arg = arguments[datetime_arg_num].type.get();
/// If time zone is attached to an argument of type DateTime.
if (const auto * type = checkAndGetDataType<DataTypeDateTime>(dt_arg))
return type->hasExplicitTimeZone() ? type->getTimeZone().getTimeZone() : std::string();
if (const auto * type = checkAndGetDataType<DataTypeDateTime64>(dt_arg))
return type->hasExplicitTimeZone() ? type->getTimeZone().getTimeZone() : std::string();
return {};
}
}
const DateLUTImpl & extractTimeZoneFromFunctionArguments(const ColumnsWithTypeAndName & arguments, size_t time_zone_arg_num, size_t datetime_arg_num)
{
if (arguments.size() == time_zone_arg_num + 1)
{
std::string time_zone = extractTimeZoneNameFromColumn(arguments[time_zone_arg_num].column.get(), arguments[time_zone_arg_num].name);
if (time_zone.empty())
throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT, "Provided time zone must be non-empty and be a valid time zone");
return DateLUT::instance(time_zone);
}
else
{
if (arguments.size() <= datetime_arg_num)
return DateLUT::instance();
const auto & dt_arg = arguments[datetime_arg_num].type.get();
/// If time zone is attached to an argument of type DateTime.
if (const auto * type = checkAndGetDataType<DataTypeDateTime>(dt_arg))
return type->getTimeZone();
if (const auto * type = checkAndGetDataType<DataTypeDateTime64>(dt_arg))
return type->getTimeZone();
return DateLUT::instance();
}
}
}