
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
return { .is_monotonic = true, .is_always_monotonic = true };
            
            if (left_in_first_half == right_in_first_half)
                return { .is_monotonic = true };
            return {};
        }
        
        if (size_of_from > size_of_to)
        {
            
            if (left.isNull() || right.isNull())
                return {};
            
            if (divideByRangeOfType(left.get<UInt64>()) != divideByRangeOfType(right.get<UInt64>()))
                return {};
            if (to_is_unsigned)
                return { .is_monotonic = true };
            else
            {
                
                const bool is_monotonic = (T(left.get<UInt64>()) >= 0) == (T(right.get<UInt64>()) >= 0);
                return { .is_monotonic = is_monotonic };
            }
        }
        __builtin_unreachable();
    }
};
struct ToDateMonotonicity
{
    static bool has() { return true; }