[ClickHouse] SHALL support proper handling of invalid time for a timezone
when using [DateTime64] extended range data type, for example,
*`2002-04-07 02:30:00` never happened at all in the US/Eastern timezone ([Stuart Bishop: pytz library](http://pytz.sourceforge.net/#problems-with-localtime))
[ClickHouse] SHALL support proper handling of invalid time when using [DateTime64] extended range data type
for a given timezone when transition from the standard to daylight saving time causes an hour to disappear.
Expected behavior: if DateTime64 initialized by a skipped time value, it is being treated as DST and resulting value will be an hour earlier, e.g. `SELECT toDateTime64('2020-03-08 02:34:00', 0, 'America/Denver')` returns `2020-03-08 01:34:00`.
[ClickHouse] SHALL support correct operation of the [toTimeZone](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#totimezone)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toQuarter](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#toquarter)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toDayOfYear](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#todayofyear)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toDayOfMonth](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#todayofmonth)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toDayOfWeek](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#todayofweek)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toUnitTimestamp](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#to-unix-timestamp)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
Timestamp value expected to be negative when DateTime64 value is prior to `1970-01-01` and positine otherwise.
[ClickHouse] SHALL support correct operation of the [toStartOfYear](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#tostartofyear)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toStartOfISOYear](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#tostartofisoyear)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toStartOfQuarter](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#tostartofquarter)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toStartOfMonth](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#tostartofmonth)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toStartOfWeek](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#tostartofweektmode)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toStartOfDay](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#tostartofday)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toStartOfHour](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#tostartofhour)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toStartOfMinute](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#tostartofminute)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toStartOfSecond](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#tostartofsecond)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toStartOfFiveMinute](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#tostartoffiveminute)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toStartOfTenMinutes](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#tostartoftenminutes)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toStartOfFifteenMinutes](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#tostartoffifteenminutes)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toStartOfInterval](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#tostartofintervaltime-or-data-interval-x-unit-time-zone)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
More detailed description can be found [here](https://github.com/ClickHouse/ClickHouse/issues/1201).
[ClickHouse] SHALL support correct operation of the [toRelativeYearNum](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#torelativeyearnum)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toRelativeQuarterNum](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#torelativequarternum)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toRelativeMonthNum](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#torelativemonthnum)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toRelativeWeekNum](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#torelativeweeknum)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toRelativeDayNum](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#torelativedaynum)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toRelativeHourNum](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#torelativehournum)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toRelativeMinuteNum](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#torelativeminutenum)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toRelativeSecondNum](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#torelativesecondnum)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toISOYear](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#toisoyear)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toISOWeek](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#toisoweek)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toWeek](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#toweekdatemode)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toYearWeek](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#toyearweekdatemode)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support conversion of output from the [yesterday](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#yesterday)
function to the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support conversion of output from the [timeSlot](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#timeslot)
function to the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toYYYYMMDD](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#toyyyymmdd)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [toYYYYMMDDhhmmss](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#toyyyymmddhhmmss)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [addYears](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#addyears-addmonths-addweeks-adddays-addhours-addminutes-addseconds-addquarters)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [addMonths](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#addyears-addmonths-addweeks-adddays-addhours-addminutes-addseconds-addquarters)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [addWeeks](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#addyears-addmonths-addweeks-adddays-addhours-addminutes-addseconds-addquarters)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [addDays](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#addyears-addmonths-addweeks-adddays-addhours-addminutes-addseconds-addquarters)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [addHours](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#addyears-addmonths-addweeks-adddays-addhours-addminutes-addseconds-addquarters)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [addMinutes](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#addyears-addmonths-addweeks-adddays-addhours-addminutes-addseconds-addquarters)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [addSeconds](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#addyears-addmonths-addweeks-adddays-addhours-addminutes-addseconds-addquarters)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [addQuarters](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#addyears-addmonths-addweeks-adddays-addhours-addminutes-addseconds-addquarters)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [subtractYears](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#subtractyears-subtractmonths-subtractweeks-subtractdays-subtracthours-subtractminutes-subtractseconds-subtractquarters)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [subtractMonths](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#subtractyears-subtractmonths-subtractweeks-subtractdays-subtracthours-subtractminutes-subtractseconds-subtractquarters)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [subtractWeeks](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#subtractyears-subtractmonths-subtractweeks-subtractdays-subtracthours-subtractminutes-subtractseconds-subtractquarters)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [subtractDays](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#subtractyears-subtractmonths-subtractweeks-subtractdays-subtracthours-subtractminutes-subtractseconds-subtractquarters)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [subtractHours](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#subtractyears-subtractmonths-subtractweeks-subtractdays-subtracthours-subtractminutes-subtractseconds-subtractquarters)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [subtractMinutes](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#subtractyears-subtractmonths-subtractweeks-subtractdays-subtracthours-subtractminutes-subtractseconds-subtractquarters)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [subtractSeconds](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#subtractyears-subtractmonths-subtractweeks-subtractdays-subtracthours-subtractminutes-subtractseconds-subtractquarters)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [subtractQuarters](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#subtractyears-subtractmonths-subtractweeks-subtractdays-subtracthours-subtractminutes-subtractseconds-subtractquarters)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [timeSlots](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#timeslotsstarttime-duration-size)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct operation of the [formatDateTime](https://clickhouse.tech/docs/en/sql-reference/functions/date-time-functions/#formatdatetime)
function used with the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct conversion of the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range]
to integer types using [toInt(8|16|32|64|128|256)](https://clickhouse.tech/docs/en/sql-reference/functions/type-conversion-functions/#toint8163264128256) functions.
[ClickHouse] SHALL support correct conversion of the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range]
to unsigned integer types using [toUInt(8|16|32|64|256)](https://clickhouse.tech/docs/en/sql-reference/functions/type-conversion-functions/#touint8163264256) functions.
[ClickHouse] SHALL support correct conversion of the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range]
to float types using [toFloat(32|64)](https://clickhouse.tech/docs/en/sql-reference/functions/type-conversion-functions/#tofloat3264) functions.
[ClickHouse] SHALL support correct conversion of the [DateTime64] data type when it stores dates within the [normal date range]
to the [Date](https://clickhouse.tech/docs/en/sql-reference/data-types/date/) type using the [toDate](https://clickhouse.tech/docs/en/sql-reference/functions/type-conversion-functions/#todate) function.
This function is ONLY supposed to work in NORMAL RANGE.
[ClickHouse] SHALL support correct conversion of the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range]
to the [DateTime](https://clickhouse.tech/docs/en/sql-reference/data-types/datetime/) type using the [toDateTime](https://clickhouse.tech/docs/en/sql-reference/functions/type-conversion-functions/#todatetime) function.
This function is ONLY supposed to work in NORMAL RANGE.
[ClickHouse] SHALL support correct conversion from the data types supported by the [toDateTime64](https://clickhouse.tech/docs/en/sql-reference/data-types/datetime64/) function
to the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range].
[ClickHouse] SHALL support correct conversion of the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range]
to [Decimal](https://clickhouse.tech/docs/en/sql-reference/data-types/decimal/) types using [toDecimal(32|64|128|256)](https://clickhouse.tech/docs/en/sql-reference/functions/type-conversion-functions/#todecimal3264128256) functions.
[ClickHouse] SHALL support correct conversion of the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range]
to the [String](https://clickhouse.tech/docs/en/sql-reference/data-types/string/) type using the [toString](https://clickhouse.tech/docs/en/sql-reference/functions/type-conversion-functions/#tostring) function.
[ClickHouse] SHALL support correct conversion of the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range]
to one of the supported data type using the [CAST(x,T)](https://clickhouse.tech/docs/en/sql-reference/functions/type-conversion-functions/#type_conversion_function-cast) function.
[ClickHouse] SHALL support correct conversion of the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range]
to the [Int64](https://clickhouse.tech/docs/en/sql-reference/data-types/int-uint/) type using the [toUnixTimestamp64Milli](https://clickhouse.tech/docs/en/sql-reference/functions/type-conversion-functions/#tounixtimestamp64milli) function.
[ClickHouse] SHALL support correct conversion of the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range]
to the [Int64](https://clickhouse.tech/docs/en/sql-reference/data-types/int-uint/) type using the [toUnixTimestamp64Micro](https://clickhouse.tech/docs/en/sql-reference/functions/type-conversion-functions/#tounixtimestamp64micro) function.
[ClickHouse] SHALL support correct conversion of the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range]
to the [Int64](https://clickhouse.tech/docs/en/sql-reference/data-types/int-uint/) type using the [toUnixTimestamp64Nano](https://clickhouse.tech/docs/en/sql-reference/functions/type-conversion-functions/#tounixtimestamp64nano) function.
[ClickHouse] SHALL support correct conversion from the [Int64](https://clickhouse.tech/docs/en/sql-reference/data-types/int-uint/) type
to the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range]
using the [fromUnixTimestamp64Milli](https://clickhouse.tech/docs/en/sql-reference/functions/type-conversion-functions/#fromunixtimestamp64milli) function.
[ClickHouse] SHALL support correct conversion from the [Int64](https://clickhouse.tech/docs/en/sql-reference/data-types/int-uint/) type
to the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range]
using the [fromUnixTimestamp64Micro](https://clickhouse.tech/docs/en/sql-reference/functions/type-conversion-functions/#fromunixtimestamp64micro) function.
[ClickHouse] SHALL support correct conversion from the [Int64](https://clickhouse.tech/docs/en/sql-reference/data-types/int-uint/) type
to the [DateTime64] data type when it stores dates within the [normal date range] and the [extended date range]
using the [fromUnixTimestamp64Nano](https://clickhouse.tech/docs/en/sql-reference/functions/type-conversion-functions/#fromunixtimestamp64nano) function.
