
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
{
    Throw,  
    Zero,   
    Null    
};
enum class ConvertFromStringParsingMode
{
    Normal,
    BestEffort,  
    BestEffortUS
};
template <typename FromDataType, typename ToDataType, typename Name,
    ConvertFromStringExceptionMode exception_mode, ConvertFromStringParsingMode parsing_mode>
struct ConvertThroughParsing
{
    static_assert(std::is_same_v<FromDataType, DataTypeString> || std::is_same_v<FromDataType, DataTypeFixedString>,
        "ConvertThroughParsing is only applicable for String or FixedString data types");
    static constexpr bool to_datetime64 = std::is_same_v<ToDataType, DataTypeDateTime64>;
    static bool isAllRead(ReadBuffer & in)