
select toDateTime64(-86400 ,9,'UTC') ==  1969-12-31 00:00:00.000000000

select toDateTime64(-86400.00 ,9,'UTC') ==  1970-01-01 00:00:00.000000000 


However, I expect both outputs to be same. 

Version affected : 22.8
using FunctionToInt64OrNull = FunctionConvertFromString<DataTypeInt64, NameToInt64OrNull, ConvertFromStringExceptionMode::Null>;
using FunctionToInt128OrNull = FunctionConvertFromString<DataTypeInt128, NameToInt128OrNull, ConvertFromStringExceptionMode::Null>;
using FunctionToInt256OrNull = FunctionConvertFromString<DataTypeInt256, NameToInt256OrNull, ConvertFromStringExceptionMode::Null>;
using FunctionToFloat32OrNull = FunctionConvertFromString<DataTypeFloat32, NameToFloat32OrNull, ConvertFromStringExceptionMode::Null>;
using FunctionToFloat64OrNull = FunctionConvertFromString<DataTypeFloat64, NameToFloat64OrNull, ConvertFromStringExceptionMode::Null>;
using FunctionToDateOrNull = FunctionConvertFromString<DataTypeDate, NameToDateOrNull, ConvertFromStringExceptionMode::Null>;
using FunctionToDate32OrNull = FunctionConvertFromString<DataTypeDate32, NameToDate32OrNull, ConvertFromStringExceptionMode::Null>;
using FunctionToDateTimeOrNull = FunctionConvertFromString<DataTypeDateTime, NameToDateTimeOrNull, ConvertFromStringExceptionMode::Null>;
using FunctionToDateTime64OrNull = FunctionConvertFromString<DataTypeDateTime64, NameToDateTime64OrNull, ConvertFromStringExceptionMode::Null>;
using FunctionToDecimal32OrNull = FunctionConvertFromString<DataTypeDecimal<Decimal32>, NameToDecimal32OrNull, ConvertFromStringExceptionMode::Null>;
using FunctionToDecimal64OrNull = FunctionConvertFromString<DataTypeDecimal<Decimal64>, NameToDecimal64OrNull, ConvertFromStringExceptionMode::Null>;
using FunctionToDecimal128OrNull = FunctionConvertFromString<DataTypeDecimal<Decimal128>, NameToDecimal128OrNull, ConvertFromStringExceptionMode::Null>;
using FunctionToDecimal256OrNull = FunctionConvertFromString<DataTypeDecimal<Decimal256>, NameToDecimal256OrNull, ConvertFromStringExceptionMode::Null>;
using FunctionToUUIDOrNull = FunctionConvertFromString<DataTypeUUID, NameToUUIDOrNull, ConvertFromStringExceptionMode::Null>;
struct NameParseDateTimeBestEffort { static constexpr auto name = "parseDateTimeBestEffort"; };
struct NameParseDateTimeBestEffortOrZero { static constexpr auto name = "parseDateTimeBestEffortOrZero"; };
struct NameParseDateTimeBestEffortOrNull { static constexpr auto name = "parseDateTimeBestEffortOrNull"; };
struct NameParseDateTimeBestEffortUS { static constexpr auto name = "parseDateTimeBestEffortUS"; };
struct NameParseDateTimeBestEffortUSOrZero { static constexpr auto name = "parseDateTimeBestEffortUSOrZero"; };
struct NameParseDateTimeBestEffortUSOrNull { static constexpr auto name = "parseDateTimeBestEffortUSOrNull"; };
struct NameParseDateTime32BestEffort { static constexpr auto name = "parseDateTime32BestEffort"; };
struct NameParseDateTime32BestEffortOrZero { static constexpr auto name = "parseDateTime32BestEffortOrZero"; };
struct NameParseDateTime32BestEffortOrNull { static constexpr auto name = "parseDateTime32BestEffortOrNull"; };
struct NameParseDateTime64BestEffort { static constexpr auto name = "parseDateTime64BestEffort"; };
struct NameParseDateTime64BestEffortOrZero { static constexpr auto name = "parseDateTime64BestEffortOrZero"; };
struct NameParseDateTime64BestEffortOrNull { static constexpr auto name = "parseDateTime64BestEffortOrNull"; };
struct NameParseDateTime64BestEffortUS { static constexpr auto name = "parseDateTime64BestEffortUS"; };
struct NameParseDateTime64BestEffortUSOrZero { static constexpr auto name = "parseDateTime64BestEffortUSOrZero"; };
struct NameParseDateTime64BestEffortUSOrNull { static constexpr auto name = "parseDateTime64BestEffortUSOrNull"; };
using FunctionParseDateTimeBestEffort = FunctionConvertFromString<