`select parseDateTimeBestEffort('01/12/2017, 18:31:44')`

It is confused by a comma - should be easy to fix.
bool has_time = false;
    bool has_time_zone_offset = false;
    bool time_zone_offset_negative = false;
    UInt8 time_zone_offset_hour = 0;
    UInt8 time_zone_offset_minute = 0;
    bool is_am = false;
    bool is_pm = false;
    auto read_alpha_month = [&month] (const auto & alpha)
    {
        if (0 == strncasecmp(alpha, "Jan", 3)) month = 1;
        else if (0 == strncasecmp(alpha, "Feb", 3)) month = 2;
        else if (0 == strncasecmp(alpha, "Mar", 3)) month = 3;
        else if (0 == strncasecmp(alpha, "Apr", 3)) month = 4;
        else if (0 == strncasecmp(alpha, "May", 3)) month = 5;
        else if (0 == strncasecmp(alpha, "Jun", 3)) month = 6;
        else if (0 == strncasecmp(alpha, "Jul", 3)) month = 7;
        else if (0 == strncasecmp(alpha, "Aug", 3)) month = 8;
        else if (0 == strncasecmp(alpha, "Sep", 3)) month = 9;
        else if (0 == strncasecmp(alpha, "Oct", 3)) month = 10;
        else if (0 == strncasecmp(alpha, "Nov", 3)) month = 11;
        else if (0 == strncasecmp(alpha, "Dec", 3)) month = 12;
        else
            return false;
        return true;
    };
    while (!in.eof())
    {
        char digits[std::numeric_limits<UInt64>::digits10];
        size_t num_digits = 0;
        if (!year || !has_time)