ClickHouse/dbms/src/Functions/FunctionsDateTime.h

#pragma once

#include <DataTypes/DataTypesNumber.h>
#include <DataTypes/DataTypeDate.h>
#include <DataTypes/DataTypeDateTime.h>
#include <DataTypes/DataTypeArray.h>
#include <DataTypes/DataTypeString.h>

#include <Columns/ColumnsNumber.h>
#include <Columns/ColumnConst.h>
#include <Columns/ColumnArray.h>
#include <Columns/ColumnString.h>
#include <Columns/ColumnFixedString.h>

#include <Common/typeid_cast.h>

#include <IO/WriteHelpers.h>

#include <Functions/IFunction.h>
#include <Functions/FunctionHelpers.h>

#include <common/DateLUT.h>

#include <type_traits>


namespace DB
{

namespace ErrorCodes
{
    extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
}

/** Functions for working with date and time.
  *
  * toYear, toMonth, toDayOfMonth, toDayOfWeek, toHour, toMinute, toSecond,
  * toMonday, toStartOfMonth, toStartOfYear, toStartOfMinute, toStartOfFiveMinute
  * toStartOfHour, toTime,
  * now, today, yesterday
  * TODO: makeDate, makeDateTime
  *
  * (toDate - located in FunctionConversion.h file)
  *
  * Return types:
  *  toYear -> UInt16
  *  toMonth, toDayOfMonth, toDayOfWeek, toHour, toMinute, toSecond -> UInt8
  *  toMonday, toStartOfMonth, toStartOfYear -> Date
  *  toStartOfMinute, toStartOfHour, toTime, now -> DateTime
  *
  * And also:
  *
  * timeSlot(EventTime)
  * - rounds the time to half an hour.
  *
  * timeSlots(StartTime, Duration)
  * - for the time interval beginning at `StartTime` and continuing `Duration` seconds,
  *   returns an array of time points, consisting of rounding down to half an hour of points from this interval.
  *  For example, timeSlots(toDateTime('2012-01-01 12:20:00'), 600) = [toDateTime('2012-01-01 12:00:00'), toDateTime('2012-01-01 12:30:00')].
  *  This is necessary to search for hits that are part of the corresponding visit.
  */


#define TIME_SLOT_SIZE 1800

/** Extra transformations.
  * Represents two functions - from datetime (UInt32) and from date (UInt16).
  *
  * Also, the "factor transformation" F is defined for the T transformation.
  * This is a transformation of F such that its value identifies the region of monotonicity T
  *  (for a fixed value of F, the transformation T is monotonic).
  *
  * Or, figuratively, if T is similar to taking the remainder of division, then F is similar to division.
  *
  * Example: to convert T "get the day number in the month" (2015-02-03 -> 3),
  *  factor-transformation F is "round to the nearest month" (2015-02-03 -> 2015-02-01).
  */

/// This factor transformation will say that the function is monotone everywhere.
struct ZeroTransform
{
    static inline UInt16 execute(UInt32 t, const DateLUTImpl & time_zone) { return 0; }
    static inline UInt16 execute(UInt16 d, const DateLUTImpl & time_zone) { return 0; }
};

struct ToDateImpl
{
    static constexpr auto name = "toDate";

    static inline UInt16 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return UInt16(time_zone.toDayNum(t));
    }
    static inline UInt16 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        return d;
    }

    using FactorTransform = ZeroTransform;
};

struct ToStartOfDayImpl
{
    static constexpr auto name = "toStartOfDay";

    static inline UInt32 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return time_zone.toDate(t);
    }
    static inline UInt16 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        return d;
    }

    using FactorTransform = ZeroTransform;
};

struct ToMondayImpl
{
    static constexpr auto name = "toMonday";

    static inline UInt16 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return time_zone.toFirstDayNumOfWeek(time_zone.toDayNum(t));
    }
    static inline UInt16 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        return time_zone.toFirstDayNumOfWeek(DayNum_t(d));
    }

    using FactorTransform = ZeroTransform;
};

struct ToStartOfMonthImpl
{
    static constexpr auto name = "toStartOfMonth";

    static inline UInt16 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return time_zone.toFirstDayNumOfMonth(time_zone.toDayNum(t));
    }
    static inline UInt16 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        return time_zone.toFirstDayNumOfMonth(DayNum_t(d));
    }

    using FactorTransform = ZeroTransform;
};

struct ToStartOfQuarterImpl
{
    static constexpr auto name = "toStartOfQuarter";

    static inline UInt16 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return time_zone.toFirstDayNumOfQuarter(time_zone.toDayNum(t));
    }
    static inline UInt16 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        return time_zone.toFirstDayNumOfQuarter(DayNum_t(d));
    }

    using FactorTransform = ZeroTransform;
};

struct ToStartOfYearImpl
{
    static constexpr auto name = "toStartOfYear";

    static inline UInt16 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return time_zone.toFirstDayNumOfYear(time_zone.toDayNum(t));
    }
    static inline UInt16 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        return time_zone.toFirstDayNumOfYear(DayNum_t(d));
    }

    using FactorTransform = ZeroTransform;
};


struct ToTimeImpl
{
    static constexpr auto name = "toTime";

    /// When transforming to time, the date will be equated to 1970-01-02.
    static inline UInt32 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return time_zone.toTime(t) + 86400;
    }

    static inline UInt32 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        throw Exception("Illegal type Date of argument for function toTime", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
    }

    using FactorTransform = ToDateImpl;
};

struct ToStartOfMinuteImpl
{
    static constexpr auto name = "toStartOfMinute";

    static inline UInt32 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return time_zone.toStartOfMinute(t);
    }
    static inline UInt32 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        throw Exception("Illegal type Date of argument for function toStartOfMinute", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
    }

    using FactorTransform = ZeroTransform;
};

struct ToStartOfFiveMinuteImpl
{
    static constexpr auto name = "toStartOfFiveMinute";

    static inline UInt32 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return time_zone.toStartOfFiveMinute(t);
    }
    static inline UInt32 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        throw Exception("Illegal type Date of argument for function toStartOfFiveMinute", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
    }

    using FactorTransform = ZeroTransform;
};

struct ToStartOfHourImpl
{
    static constexpr auto name = "toStartOfHour";

    static inline UInt32 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return time_zone.toStartOfHour(t);
    }

    static inline UInt32 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        throw Exception("Illegal type Date of argument for function toStartOfHour", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
    }

    using FactorTransform = ZeroTransform;
};

struct ToYearImpl
{
    static constexpr auto name = "toYear";

    static inline UInt16 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return time_zone.toYear(t);
    }
    static inline UInt16 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        return time_zone.toYear(DayNum_t(d));
    }

    using FactorTransform = ZeroTransform;
};

struct ToMonthImpl
{
    static constexpr auto name = "toMonth";

    static inline UInt8 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return time_zone.toMonth(t);
    }
    static inline UInt8 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        return time_zone.toMonth(DayNum_t(d));
    }

    using FactorTransform = ToStartOfYearImpl;
};

struct ToDayOfMonthImpl
{
    static constexpr auto name = "toDayOfMonth";

    static inline UInt8 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return time_zone.toDayOfMonth(t);
    }
    static inline UInt8 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        return time_zone.toDayOfMonth(DayNum_t(d));
    }

    using FactorTransform = ToStartOfMonthImpl;
};

struct ToDayOfWeekImpl
{
    static constexpr auto name = "toDayOfWeek";

    static inline UInt8 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return time_zone.toDayOfWeek(t);
    }
    static inline UInt8 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        return time_zone.toDayOfWeek(DayNum_t(d));
    }

    using FactorTransform = ToMondayImpl;
};

struct ToHourImpl
{
    static constexpr auto name = "toHour";

    static inline UInt8 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return time_zone.toHour(t);
    }

    static inline UInt8 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        throw Exception("Illegal type Date of argument for function toHour", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
    }

    using FactorTransform = ToDateImpl;
};

struct ToMinuteImpl
{
    static constexpr auto name = "toMinute";

    static inline UInt8 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return time_zone.toMinute(t);
    }
    static inline UInt8 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        throw Exception("Illegal type Date of argument for function toMinute", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
    }

    using FactorTransform = ToStartOfHourImpl;
};

struct ToSecondImpl
{
    static constexpr auto name = "toSecond";

    static inline UInt8 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return time_zone.toSecond(t);
    }
    static inline UInt8 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        throw Exception("Illegal type Date of argument for function toSecond", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
    }

    using FactorTransform = ToStartOfMinuteImpl;
};

struct ToRelativeYearNumImpl
{
    static constexpr auto name = "toRelativeYearNum";

    static inline UInt16 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return time_zone.toYear(t);
    }
    static inline UInt16 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        return time_zone.toYear(DayNum_t(d));
    }

    using FactorTransform = ZeroTransform;
};

struct ToRelativeMonthNumImpl
{
    static constexpr auto name = "toRelativeMonthNum";

    static inline UInt16 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return time_zone.toRelativeMonthNum(t);
    }
    static inline UInt16 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        return time_zone.toRelativeMonthNum(DayNum_t(d));
    }

    using FactorTransform = ZeroTransform;
};

struct ToRelativeWeekNumImpl
{
    static constexpr auto name = "toRelativeWeekNum";

    static inline UInt16 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return time_zone.toRelativeWeekNum(t);
    }
    static inline UInt16 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        return time_zone.toRelativeWeekNum(DayNum_t(d));
    }

    using FactorTransform = ZeroTransform;
};

struct ToRelativeDayNumImpl
{
    static constexpr auto name = "toRelativeDayNum";

    static inline UInt16 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return time_zone.toDayNum(t);
    }
    static inline UInt16 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        return static_cast<DayNum_t>(d);
    }

    using FactorTransform = ZeroTransform;
};


struct ToRelativeHourNumImpl
{
    static constexpr auto name = "toRelativeHourNum";

    static inline UInt32 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return time_zone.toRelativeHourNum(t);
    }
    static inline UInt32 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        throw Exception("Illegal type Date of argument for function toRelativeHourNum", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
    }

    using FactorTransform = ZeroTransform;
};

struct ToRelativeMinuteNumImpl
{
    static constexpr auto name = "toRelativeMinuteNum";

    static inline UInt32 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return time_zone.toRelativeMinuteNum(t);
    }
    static inline UInt32 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        throw Exception("Illegal type Date of argument for function toRelativeMinuteNum", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
    }

    using FactorTransform = ZeroTransform;
};

struct ToRelativeSecondNumImpl
{
    static constexpr auto name = "toRelativeSecondNum";

    static inline UInt32 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return t;
    }
    static inline UInt32 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        throw Exception("Illegal type Date of argument for function toRelativeSecondNum", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
    }

    using FactorTransform = ZeroTransform;
};

struct ToYYYYMMImpl
{
    static constexpr auto name = "toYYYYMM";

    static inline UInt32 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return time_zone.toNumYYYYMM(t);
    }
    static inline UInt32 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        return time_zone.toNumYYYYMM(static_cast<DayNum_t>(d));
    }

    using FactorTransform = ZeroTransform;
};

struct ToYYYYMMDDImpl
{
    static constexpr auto name = "toYYYYMMDD";

    static inline UInt32 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return time_zone.toNumYYYYMMDD(t);
    }
    static inline UInt32 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        return time_zone.toNumYYYYMMDD(static_cast<DayNum_t>(d));
    }

    using FactorTransform = ZeroTransform;
};

struct ToYYYYMMDDhhmmssImpl
{
    static constexpr auto name = "toYYYYMMDDhhmmss";

    static inline UInt64 execute(UInt32 t, const DateLUTImpl & time_zone)
    {
        return time_zone.toNumYYYYMMDDhhmmss(t);
    }
    static inline UInt64 execute(UInt16 d, const DateLUTImpl & time_zone)
    {
        return time_zone.toNumYYYYMMDDhhmmss(time_zone.toDate(static_cast<DayNum_t>(d)));
    }

    using FactorTransform = ZeroTransform;
};


template <typename FromType, typename ToType, typename Transform>
struct Transformer
{
    static void vector(const PaddedPODArray<FromType> & vec_from, PaddedPODArray<ToType> & vec_to, const DateLUTImpl & time_zone)
    {
        size_t size = vec_from.size();
        vec_to.resize(size);

        for (size_t i = 0; i < size; ++i)
            vec_to[i] = Transform::execute(vec_from[i], time_zone);
    }
};


template <typename FromType, typename ToType, typename Transform>
struct DateTimeTransformImpl
{
    static void execute(Block & block, const ColumnNumbers & arguments, size_t result)
    {
        using Op = Transformer<FromType, ToType, Transform>;

        const ColumnConst * time_zone_column = nullptr;

        if (arguments.size() == 2)
        {
            time_zone_column = checkAndGetColumnConst<ColumnString>(block.getByPosition(arguments[1]).column.get());

            if (!time_zone_column)
                throw Exception("Illegal column " + block.getByPosition(arguments[1]).column->getName()
                    + " of second (time zone) argument of function " + Transform::name + ", must be constant string",
                    ErrorCodes::ILLEGAL_COLUMN);
        }

        const DateLUTImpl & time_zone = time_zone_column
            ? DateLUT::instance(time_zone_column->getValue<String>())
            : DateLUT::instance();

        const ColumnPtr source_col = block.getByPosition(arguments[0]).column;
        if (const auto * sources = checkAndGetColumn<ColumnVector<FromType>>(source_col.get()))
        {
            auto col_to = std::make_shared<ColumnVector<ToType>>();
            block.getByPosition(result).column = col_to;
            Op::vector(sources->getData(), col_to->getData(), time_zone);
        }
        else
        {
            throw Exception("Illegal column " + block.getByPosition(arguments[0]).column->getName()
                + " of first argument of function " + Transform::name,
                ErrorCodes::ILLEGAL_COLUMN);
        }
    }
};


template <typename ToDataType, typename Transform>
class FunctionDateOrDateTimeToSomething : public IFunction
{
public:
    static constexpr auto name = Transform::name;
    static FunctionPtr create(const Context & context) { return std::make_shared<FunctionDateOrDateTimeToSomething>(); };

    String getName() const override
    {
        return name;
    }

    bool isVariadic() const override { return true; }
    size_t getNumberOfArguments() const override { return 0; }

    DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
    {
        if (arguments.size() == 1)
        {
            if (!checkDataType<DataTypeDate>(arguments[0].get())
                && !checkDataType<DataTypeDateTime>(arguments[0].get()))
                throw Exception{
                    "Illegal type " + arguments[0]->getName() + " of argument of function " + getName() +
                    ". Should be a date or a date with time", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT};
        }
        else if (arguments.size() == 2)
        {
            if (!checkDataType<DataTypeDateTime>(arguments[0].get())
                || !checkDataType<DataTypeString>(arguments[1].get()))
                throw Exception{
                    "Function " + getName() + " supports 1 or 2 arguments. The 1st argument "
                    "must be of type Date or DateTime. The 2nd argument (optional) must be "
                    "a constant string with timezone name. The timezone argument is allowed "
                    "only when the 1st argument has the type DateTime",
                    ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT};
        }
        else
            throw Exception("Number of arguments for function " + getName() + " doesn't match: passed "
                + toString(arguments.size()) + ", should be 1 or 2",
                ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);

        return std::make_shared<ToDataType>();
    }

    bool useDefaultImplementationForConstants() const override { return true; }
    ColumnNumbers getArgumentsThatAreAlwaysConstant() const override { return {1}; }

    void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result) override
    {
        const IDataType * from_type = block.getByPosition(arguments[0]).type.get();

        if (checkDataType<DataTypeDate>(from_type))
            DateTimeTransformImpl<DataTypeDate::FieldType, typename ToDataType::FieldType, Transform>::execute(block, arguments, result);
        else if (checkDataType<DataTypeDateTime>(from_type))
            DateTimeTransformImpl<DataTypeDateTime::FieldType, typename ToDataType::FieldType, Transform>::execute(block, arguments, result);
        else
            throw Exception("Illegal type " + block.getByPosition(arguments[0]).type->getName() + " of argument of function " + getName(),
                ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
    }


    bool hasInformationAboutMonotonicity() const override
    {
        return true;
    }

    Monotonicity getMonotonicityForRange(const IDataType & type, const Field & left, const Field & right) const override
    {
        IFunction::Monotonicity is_monotonic { true };
        IFunction::Monotonicity is_not_monotonic;

        if (std::is_same<typename Transform::FactorTransform, ZeroTransform>::value)
        {
            is_monotonic.is_always_monotonic = true;
            return is_monotonic;
        }

        /// This method is called only if the function has one argument. Therefore, we do not care about the non-local time zone.
        const DateLUTImpl & date_lut = DateLUT::instance();

        if (left.isNull() || right.isNull())
            return is_not_monotonic;

        /// The function is monotonous on the [left, right] segment, if the factor transformation returns the same values for them.

        if (checkAndGetDataType<DataTypeDate>(&type))
        {
            return Transform::FactorTransform::execute(UInt16(left.get<UInt64>()), date_lut)
                == Transform::FactorTransform::execute(UInt16(right.get<UInt64>()), date_lut)
                ? is_monotonic : is_not_monotonic;
        }
        else
        {
            return Transform::FactorTransform::execute(UInt32(left.get<UInt64>()), date_lut)
                == Transform::FactorTransform::execute(UInt32(right.get<UInt64>()), date_lut)
                ? is_monotonic : is_not_monotonic;
        }
    }
};


struct AddSecondsImpl
{
    static constexpr auto name = "addSeconds";

    static inline UInt32 execute(UInt32 t, Int64 delta, const DateLUTImpl & time_zone)
    {
        return t + delta;
    }

    static inline UInt32 execute(UInt16 d, Int64 delta, const DateLUTImpl & time_zone)
    {
        return time_zone.fromDayNum(DayNum_t(d)) + delta;
    }
};

struct AddMinutesImpl
{
    static constexpr auto name = "addMinutes";

    static inline UInt32 execute(UInt32 t, Int64 delta, const DateLUTImpl & time_zone)
    {
        return t + delta * 60;
    }

    static inline UInt32 execute(UInt16 d, Int64 delta, const DateLUTImpl & time_zone)
    {
        return time_zone.fromDayNum(DayNum_t(d)) + delta * 60;
    }
};

struct AddHoursImpl
{
    static constexpr auto name = "addHours";

    static inline UInt32 execute(UInt32 t, Int64 delta, const DateLUTImpl & time_zone)
    {
        return t + delta * 3600;
    }

    static inline UInt32 execute(UInt16 d, Int64 delta, const DateLUTImpl & time_zone)
    {
        return time_zone.fromDayNum(DayNum_t(d)) + delta * 3600;
    }
};

struct AddDaysImpl
{
    static constexpr auto name = "addDays";

    static inline UInt32 execute(UInt32 t, Int64 delta, const DateLUTImpl & time_zone)
    {
        return time_zone.addDays(t, delta);
    }

    static inline UInt16 execute(UInt16 d, Int64 delta, const DateLUTImpl & time_zone)
    {
        return d + delta;
    }
};

struct AddWeeksImpl
{
    static constexpr auto name = "addWeeks";

    static inline UInt32 execute(UInt32 t, Int64 delta, const DateLUTImpl & time_zone)
    {
        return time_zone.addWeeks(t, delta);
    }

    static inline UInt16 execute(UInt16 d, Int64 delta, const DateLUTImpl & time_zone)
    {
        return d + delta * 7;
    }
};

struct AddMonthsImpl
{
    static constexpr auto name = "addMonths";

    static inline UInt32 execute(UInt32 t, Int64 delta, const DateLUTImpl & time_zone)
    {
        return time_zone.addMonths(t, delta);
    }

    static inline UInt16 execute(UInt16 d, Int64 delta, const DateLUTImpl & time_zone)
    {
        return time_zone.addMonths(DayNum_t(d), delta);
    }
};

struct AddYearsImpl
{
    static constexpr auto name = "addYears";

    static inline UInt32 execute(UInt32 t, Int64 delta, const DateLUTImpl & time_zone)
    {
        return time_zone.addYears(t, delta);
    }

    static inline UInt16 execute(UInt16 d, Int64 delta, const DateLUTImpl & time_zone)
    {
        return time_zone.addYears(DayNum_t(d), delta);
    }
};


template <typename Transform>
struct SubtractIntervalImpl
{
    static inline UInt32 execute(UInt32 t, Int64 delta, const DateLUTImpl & time_zone)
    {
        return Transform::execute(t, -delta, time_zone);
    }

    static inline UInt16 execute(UInt16 d, Int64 delta, const DateLUTImpl & time_zone)
    {
        return Transform::execute(d, -delta, time_zone);
    }
};

struct SubtractSecondsImpl : SubtractIntervalImpl<AddSecondsImpl> { static constexpr auto name = "subtractSeconds"; };
struct SubtractMinutesImpl : SubtractIntervalImpl<AddMinutesImpl> { static constexpr auto name = "subtractMinutes"; };
struct SubtractHoursImpl : SubtractIntervalImpl<AddHoursImpl> { static constexpr auto name = "subtractHours"; };
struct SubtractDaysImpl : SubtractIntervalImpl<AddDaysImpl> { static constexpr auto name = "subtractDays"; };
struct SubtractWeeksImpl : SubtractIntervalImpl<AddWeeksImpl> { static constexpr auto name = "subtractWeeks"; };
struct SubtractMonthsImpl : SubtractIntervalImpl<AddMonthsImpl> { static constexpr auto name = "subtractMonths"; };
struct SubtractYearsImpl : SubtractIntervalImpl<AddYearsImpl> { static constexpr auto name = "subtractYears"; };


template <typename FromType, typename ToType, typename Transform>
struct Adder
{
    static void vector_vector(const PaddedPODArray<FromType> & vec_from, PaddedPODArray<ToType> & vec_to, const IColumn & delta, const DateLUTImpl & time_zone)
    {
        size_t size = vec_from.size();
        vec_to.resize(size);

        for (size_t i = 0; i < size; ++i)
            vec_to[i] = Transform::execute(vec_from[i], delta.getInt(i), time_zone);
    }

    static void vector_constant(const PaddedPODArray<FromType> & vec_from, PaddedPODArray<ToType> & vec_to, Int64 delta, const DateLUTImpl & time_zone)
    {
        size_t size = vec_from.size();
        vec_to.resize(size);

        for (size_t i = 0; i < size; ++i)
            vec_to[i] = Transform::execute(vec_from[i], delta, time_zone);
    }

    static void constant_vector(const FromType & from, PaddedPODArray<ToType> & vec_to, const IColumn & delta, const DateLUTImpl & time_zone)
    {
        size_t size = delta.size();
        vec_to.resize(size);

        for (size_t i = 0; i < size; ++i)
            vec_to[i] = Transform::execute(from, delta.getInt(i), time_zone);
    }
};


template <typename FromType, typename Transform>
struct DateTimeAddIntervalImpl
{
    static void execute(Block & block, const ColumnNumbers & arguments, size_t result)
    {
        using ToType = decltype(Transform::execute(FromType(), 0, std::declval<DateLUTImpl>()));
        using Op = Adder<FromType, ToType, Transform>;

        const ColumnConst * time_zone_column = nullptr;

        if (arguments.size() == 3)
        {
            time_zone_column = checkAndGetColumnConst<ColumnString>(block.getByPosition(arguments[2]).column.get());

            if (!time_zone_column)
                throw Exception("Illegal column " + block.getByPosition(arguments[2]).column->getName()
                    + " of second (time zone) argument of function " + Transform::name + ", must be constant string",
                    ErrorCodes::ILLEGAL_COLUMN);
        }

        const DateLUTImpl & time_zone = time_zone_column
            ? DateLUT::instance(time_zone_column->getValue<String>())
            : DateLUT::instance();

        const ColumnPtr source_col = block.getByPosition(arguments[0]).column;

        if (const auto * sources = checkAndGetColumn<ColumnVector<FromType>>(source_col.get()))
        {
            auto col_to = std::make_shared<ColumnVector<ToType>>();
            block.getByPosition(result).column = col_to;

            const IColumn & delta_column = *block.getByPosition(arguments[1]).column;

            if (const auto * delta_const_column = typeid_cast<const ColumnConst *>(&delta_column))
                Op::vector_constant(sources->getData(), col_to->getData(), delta_const_column->getValue<Int64>(), time_zone);
            else
                Op::vector_vector(sources->getData(), col_to->getData(), delta_column, time_zone);
        }
        else if (const auto * sources = checkAndGetColumnConst<ColumnVector<FromType>>(source_col.get()))
        {
            auto col_to = std::make_shared<ColumnVector<ToType>>();
            block.getByPosition(result).column = col_to;
            Op::constant_vector(sources->template getValue<FromType>(), col_to->getData(), *block.getByPosition(arguments[1]).column, time_zone);
        }
        else
        {
            throw Exception("Illegal column " + block.getByPosition(arguments[0]).column->getName()
                + " of first argument of function " + Transform::name,
                ErrorCodes::ILLEGAL_COLUMN);
        }
    }
};


template <typename Transform>
class FunctionDateOrDateTimeAddInterval : public IFunction
{
public:
    static constexpr auto name = Transform::name;
    static FunctionPtr create(const Context & context) { return std::make_shared<FunctionDateOrDateTimeAddInterval>(); };

    String getName() const override
    {
        return name;
    }

    bool isVariadic() const override { return true; }
    size_t getNumberOfArguments() const override { return 0; }

    DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
    {
        if (arguments.size() != 2 && arguments.size() != 3)
            throw Exception("Number of arguments for function " + getName() + " doesn't match: passed "
                + toString(arguments.size()) + ", should be 2 or 3",
                ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);

        if (!arguments[1]->behavesAsNumber())
            throw Exception("Second argument for function " + getName() + " (delta) must be number",
                ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);

        if (arguments.size() == 2)
        {
            if (!checkDataType<DataTypeDate>(arguments[0].get())
                && !checkDataType<DataTypeDateTime>(arguments[0].get()))
                throw Exception{
                    "Illegal type " + arguments[0]->getName() + " of argument of function " + getName() +
                    ". Should be a date or a date with time", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT};
        }
        else
        {
            if (!checkDataType<DataTypeDateTime>(arguments[0].get())
                || !checkDataType<DataTypeString>(arguments[1].get()))
                throw Exception{
                    "Function " + getName() + " supports 2 or 3 arguments. The 1st argument "
                    "must be of type Date or DateTime. The 2nd argument must be number. "
                    "The 3rd argument (optional) must be "
                    "a constant string with timezone name. The timezone argument is allowed "
                    "only when the 1st argument has the type DateTime",
                    ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT};
        }

        if (checkDataType<DataTypeDate>(arguments[0].get()))
            return std::make_shared<typename std::conditional<std::is_same<
                decltype(Transform::execute(DataTypeDate::FieldType(), 0, std::declval<DateLUTImpl>())), UInt16>::value,
                DataTypeDate, DataTypeDateTime>::type>();
        else
            return std::make_shared<typename std::conditional<std::is_same<
                decltype(Transform::execute(DataTypeDateTime::FieldType(), 0, std::declval<DateLUTImpl>())), UInt16>::value,
                DataTypeDate, DataTypeDateTime>::type>();
    }

    bool useDefaultImplementationForConstants() const override { return true; }
    ColumnNumbers getArgumentsThatAreAlwaysConstant() const override { return {2}; }

    void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result) override
    {
        const IDataType * from_type = block.getByPosition(arguments[0]).type.get();

        if (checkDataType<DataTypeDate>(from_type))
            DateTimeAddIntervalImpl<DataTypeDate::FieldType, Transform>::execute(block, arguments, result);
        else if (checkDataType<DataTypeDateTime>(from_type))
            DateTimeAddIntervalImpl<DataTypeDateTime::FieldType, Transform>::execute(block, arguments, result);
        else
            throw Exception("Illegal type " + block.getByPosition(arguments[0]).type->getName() + " of argument of function " + getName(),
                ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
    }
};


/// Get the current time. (It is a constant, it is evaluated once for the entire query.)
class FunctionNow : public IFunction
{
public:
    static constexpr auto name = "now";
    static FunctionPtr create(const Context & context) { return std::make_shared<FunctionNow>(); };

    String getName() const override
    {
        return name;
    }

    size_t getNumberOfArguments() const override { return 0; }

    DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
    {
        return std::make_shared<DataTypeDateTime>();
    }

    void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result) override
    {
        block.getByPosition(result).column = DataTypeUInt32().createConstColumn(
            block.rows(),
            static_cast<UInt64>(time(0)));
    }
};


class FunctionToday : public IFunction
{
public:
    static constexpr auto name = "today";
    static FunctionPtr create(const Context & context) { return std::make_shared<FunctionToday>(); };

    String getName() const override
    {
        return name;
    }

    size_t getNumberOfArguments() const override { return 0; }

    DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
    {
        return std::make_shared<DataTypeDate>();
    }

    void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result) override
    {
        block.getByPosition(result).column = DataTypeUInt16().createConstColumn(
            block.rows(),
            UInt64(DateLUT::instance().toDayNum(time(0))));
    }
};


class FunctionYesterday : public IFunction
{
public:
    static constexpr auto name = "yesterday";
    static FunctionPtr create(const Context & context) { return std::make_shared<FunctionYesterday>(); };

    String getName() const override
    {
        return name;
    }

    size_t getNumberOfArguments() const override { return 0; }

    DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
    {
        return std::make_shared<DataTypeDate>();
    }

    void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result) override
    {
        block.getByPosition(result).column = DataTypeUInt16().createConstColumn(
            block.rows(),
            UInt64(DateLUT::instance().toDayNum(time(0)) - 1));
    }
};


class FunctionTimeSlot : public IFunction
{
public:
    static constexpr auto name = "timeSlot";
    static FunctionPtr create(const Context & context) { return std::make_shared<FunctionTimeSlot>(); };

    String getName() const override
    {
        return name;
    }

    size_t getNumberOfArguments() const override { return 1; }

    DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
    {
        if (!checkDataType<DataTypeDateTime>(arguments[0].get()))
            throw Exception("Illegal type " + arguments[0]->getName() + " of first argument of function " + getName() + ". Must be DateTime.",
                ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);

        return std::make_shared<DataTypeDateTime>();
    }

    bool useDefaultImplementationForConstants() const override { return true; }

    void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result) override
    {
        if (const ColumnUInt32 * times = typeid_cast<const ColumnUInt32 *>(block.getByPosition(arguments[0]).column.get()))
        {
            auto res = std::make_shared<ColumnUInt32>();
            ColumnPtr res_holder = res;
            ColumnUInt32::Container_t & res_vec = res->getData();
            const ColumnUInt32::Container_t & vec = times->getData();

            size_t size = vec.size();
            res_vec.resize(size);

            for (size_t i = 0; i < size; ++i)
                res_vec[i] = vec[i] / TIME_SLOT_SIZE * TIME_SLOT_SIZE;

            block.getByPosition(result).column = res_holder;
        }
        else
            throw Exception("Illegal column " + block.getByPosition(arguments[0]).column->getName()
                    + " of argument of function " + getName(),
                ErrorCodes::ILLEGAL_COLUMN);
    }
};


template <typename DurationType>
struct TimeSlotsImpl
{
    static void vector_vector(
        const PaddedPODArray<UInt32> & starts, const PaddedPODArray<DurationType> & durations,
        PaddedPODArray<UInt32> & result_values, ColumnArray::Offsets_t & result_offsets)
    {
        size_t size = starts.size();

        result_offsets.resize(size);
        result_values.reserve(size);

        ColumnArray::Offset_t current_offset = 0;
        for (size_t i = 0; i < size; ++i)
        {
            for (UInt32 value = starts[i] / TIME_SLOT_SIZE; value <= (starts[i] + durations[i]) / TIME_SLOT_SIZE; ++value)
            {
                result_values.push_back(value * TIME_SLOT_SIZE);
                ++current_offset;
            }

            result_offsets[i] = current_offset;
        }
    }

    static void vector_constant(
        const PaddedPODArray<UInt32> & starts, DurationType duration,
        PaddedPODArray<UInt32> & result_values, ColumnArray::Offsets_t & result_offsets)
    {
        size_t size = starts.size();

        result_offsets.resize(size);
        result_values.reserve(size);

        ColumnArray::Offset_t current_offset = 0;
        for (size_t i = 0; i < size; ++i)
        {
            for (UInt32 value = starts[i] / TIME_SLOT_SIZE; value <= (starts[i] + duration) / TIME_SLOT_SIZE; ++value)
            {
                result_values.push_back(value * TIME_SLOT_SIZE);
                ++current_offset;
            }

            result_offsets[i] = current_offset;
        }
    }

    static void constant_vector(
        UInt32 start, const PaddedPODArray<DurationType> & durations,
        PaddedPODArray<UInt32> & result_values, ColumnArray::Offsets_t & result_offsets)
    {
        size_t size = durations.size();

        result_offsets.resize(size);
        result_values.reserve(size);

        ColumnArray::Offset_t current_offset = 0;
        for (size_t i = 0; i < size; ++i)
        {
            for (UInt32 value = start / TIME_SLOT_SIZE; value <= (start + durations[i]) / TIME_SLOT_SIZE; ++value)
            {
                result_values.push_back(value * TIME_SLOT_SIZE);
                ++current_offset;
            }

            result_offsets[i] = current_offset;
        }
    }

    static void constant_constant(
        UInt32 start, DurationType duration,
        Array & result)
    {
        for (UInt32 value = start / TIME_SLOT_SIZE; value <= (start + duration) / TIME_SLOT_SIZE; ++value)
            result.push_back(static_cast<UInt64>(value * TIME_SLOT_SIZE));
    }
};


class FunctionTimeSlots : public IFunction
{
public:
    static constexpr auto name = "timeSlots";
    static FunctionPtr create(const Context & context) { return std::make_shared<FunctionTimeSlots>(); };

    String getName() const override
    {
        return name;
    }

    size_t getNumberOfArguments() const override { return 2; }

    DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
    {
        if (!checkDataType<DataTypeDateTime>(arguments[0].get()))
            throw Exception("Illegal type " + arguments[0]->getName() + " of first argument of function " + getName() + ". Must be DateTime.",
                ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);

        if (!checkDataType<DataTypeUInt32>(arguments[1].get()))
            throw Exception("Illegal type " + arguments[1]->getName() + " of second argument of function " + getName() + ". Must be UInt32.",
                ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);

        return std::make_shared<DataTypeArray>(std::make_shared<DataTypeDateTime>());
    }

    void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result) override
    {
        auto starts = checkAndGetColumn<ColumnUInt32>(block.getByPosition(arguments[0]).column.get());
        auto const_starts = checkAndGetColumnConst<ColumnUInt32>(block.getByPosition(arguments[0]).column.get());

        auto durations = checkAndGetColumn<ColumnUInt32>(block.getByPosition(arguments[1]).column.get());
        auto const_durations = checkAndGetColumnConst<ColumnUInt32>(block.getByPosition(arguments[1]).column.get());

        auto res = std::make_shared<ColumnArray>(std::make_shared<ColumnUInt32>());
        ColumnPtr res_holder = res;
        ColumnUInt32::Container_t & res_values = typeid_cast<ColumnUInt32 &>(res->getData()).getData();

        if (starts && durations)
        {
            TimeSlotsImpl<UInt32>::vector_vector(starts->getData(), durations->getData(), res_values, res->getOffsets());
            block.getByPosition(result).column = res_holder;
        }
        else if (starts && const_durations)
        {
            TimeSlotsImpl<UInt32>::vector_constant(starts->getData(), const_durations->getValue<UInt32>(), res_values, res->getOffsets());
            block.getByPosition(result).column = res_holder;
        }
        else if (const_starts && durations)
        {
            TimeSlotsImpl<UInt32>::constant_vector(const_starts->getValue<UInt32>(), durations->getData(), res_values, res->getOffsets());
            block.getByPosition(result).column = res_holder;
        }
        else if (const_starts && const_durations)
        {
            Array const_res;
            TimeSlotsImpl<UInt32>::constant_constant(const_starts->getValue<UInt32>(), const_durations->getValue<UInt32>(), const_res);
            block.getByPosition(result).column = block.getByPosition(result).type->createConstColumn(block.rows(), const_res);
        }
        else
            throw Exception("Illegal columns " + block.getByPosition(arguments[0]).column->getName()
                    + ", " + block.getByPosition(arguments[1]).column->getName()
                    + " of arguments of function " + getName(),
                ErrorCodes::ILLEGAL_COLUMN);
    }
};


using FunctionToYear = FunctionDateOrDateTimeToSomething<DataTypeUInt16, ToYearImpl>;
using FunctionToMonth = FunctionDateOrDateTimeToSomething<DataTypeUInt8, ToMonthImpl>;
using FunctionToDayOfMonth = FunctionDateOrDateTimeToSomething<DataTypeUInt8, ToDayOfMonthImpl>;
using FunctionToDayOfWeek = FunctionDateOrDateTimeToSomething<DataTypeUInt8, ToDayOfWeekImpl>;
using FunctionToHour = FunctionDateOrDateTimeToSomething<DataTypeUInt8, ToHourImpl>;
using FunctionToMinute = FunctionDateOrDateTimeToSomething<DataTypeUInt8, ToMinuteImpl>;
using FunctionToSecond = FunctionDateOrDateTimeToSomething<DataTypeUInt8, ToSecondImpl>;
using FunctionToStartOfDay = FunctionDateOrDateTimeToSomething<DataTypeDateTime, ToStartOfDayImpl>;
using FunctionToMonday = FunctionDateOrDateTimeToSomething<DataTypeDate, ToMondayImpl>;
using FunctionToStartOfMonth = FunctionDateOrDateTimeToSomething<DataTypeDate, ToStartOfMonthImpl>;
using FunctionToStartOfQuarter = FunctionDateOrDateTimeToSomething<DataTypeDate, ToStartOfQuarterImpl>;
using FunctionToStartOfYear = FunctionDateOrDateTimeToSomething<DataTypeDate, ToStartOfYearImpl>;
using FunctionToStartOfMinute = FunctionDateOrDateTimeToSomething<DataTypeDateTime, ToStartOfMinuteImpl>;
using FunctionToStartOfFiveMinute = FunctionDateOrDateTimeToSomething<DataTypeDateTime, ToStartOfFiveMinuteImpl>;
using FunctionToStartOfHour = FunctionDateOrDateTimeToSomething<DataTypeDateTime, ToStartOfHourImpl>;
using FunctionToTime = FunctionDateOrDateTimeToSomething<DataTypeDateTime, ToTimeImpl>;

using FunctionToRelativeYearNum = FunctionDateOrDateTimeToSomething<DataTypeUInt16, ToRelativeYearNumImpl>;
using FunctionToRelativeMonthNum = FunctionDateOrDateTimeToSomething<DataTypeUInt32, ToRelativeMonthNumImpl>;
using FunctionToRelativeWeekNum = FunctionDateOrDateTimeToSomething<DataTypeUInt32, ToRelativeWeekNumImpl>;
using FunctionToRelativeDayNum = FunctionDateOrDateTimeToSomething<DataTypeUInt32, ToRelativeDayNumImpl>;

using FunctionToRelativeHourNum = FunctionDateOrDateTimeToSomething<DataTypeUInt32, ToRelativeHourNumImpl>;
using FunctionToRelativeMinuteNum = FunctionDateOrDateTimeToSomething<DataTypeUInt32, ToRelativeMinuteNumImpl>;
using FunctionToRelativeSecondNum = FunctionDateOrDateTimeToSomething<DataTypeUInt32, ToRelativeSecondNumImpl>;

using FunctionToYYYYMM = FunctionDateOrDateTimeToSomething<DataTypeUInt32, ToYYYYMMImpl>;
using FunctionToYYYYMMDD = FunctionDateOrDateTimeToSomething<DataTypeUInt32, ToYYYYMMDDImpl>;
using FunctionToYYYYMMDDhhmmss = FunctionDateOrDateTimeToSomething<DataTypeUInt64, ToYYYYMMDDhhmmssImpl>;

using FunctionAddSeconds = FunctionDateOrDateTimeAddInterval<AddSecondsImpl>;
using FunctionAddMinutes = FunctionDateOrDateTimeAddInterval<AddMinutesImpl>;
using FunctionAddHours = FunctionDateOrDateTimeAddInterval<AddHoursImpl>;
using FunctionAddDays = FunctionDateOrDateTimeAddInterval<AddDaysImpl>;
using FunctionAddWeeks = FunctionDateOrDateTimeAddInterval<AddWeeksImpl>;
using FunctionAddMonths = FunctionDateOrDateTimeAddInterval<AddMonthsImpl>;
using FunctionAddYears = FunctionDateOrDateTimeAddInterval<AddYearsImpl>;

using FunctionSubtractSeconds = FunctionDateOrDateTimeAddInterval<SubtractSecondsImpl>;
using FunctionSubtractMinutes = FunctionDateOrDateTimeAddInterval<SubtractMinutesImpl>;
using FunctionSubtractHours = FunctionDateOrDateTimeAddInterval<SubtractHoursImpl>;
using FunctionSubtractDays = FunctionDateOrDateTimeAddInterval<SubtractDaysImpl>;
using FunctionSubtractWeeks = FunctionDateOrDateTimeAddInterval<SubtractWeeksImpl>;
using FunctionSubtractMonths = FunctionDateOrDateTimeAddInterval<SubtractMonthsImpl>;
using FunctionSubtractYears = FunctionDateOrDateTimeAddInterval<SubtractYearsImpl>;

}