
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
{
        static constexpr bool throw_exception = std::is_same_v<ReturnType, void>;
        if constexpr (throw_exception)
        {
            writeString(type->getNameForValue(x), wb);
        }
        else
        {
            StringRef res;
            bool is_ok = type->getNameForValue(x, res);
            if (is_ok)
                writeString(res, wb);
            return ReturnType(is_ok);
        }
    }
};
template <typename FieldType>
struct FormatImpl<DataTypeDecimal<FieldType>>
{
    template <typename ReturnType = void>
    static ReturnType execute(const FieldType x, WriteBuffer & wb, const DataTypeDecimal<FieldType> * type, const DateLUTImpl *)