```
$ echo '20210101,A' | clickhouse-local --input-format CSV --structure 'd Date, s String' --query "SELECT * FROM table"
Code: 27. DB::Exception: Cannot parse input: expected ',' before: '20210101,A\n': 
Row 1:
Column 0,   name: d, type: Date,   ERROR: text "20210101,A" is not like Date

: While executing ParallelParsingBlockInputFormat: While executing File. (CANNOT_PARSE_INPUT_ASSERTION_FAILED)
```

**How to solve**

Disambiguate while parsing by absense of separators between YYYY-MM-DD.
minute = (s[14] - '0') * 10 + (s[15] - '0');
            second = (s[17] - '0') * 10 + (s[18] - '0');
        }
        if (unlikely(year == 0))
            datetime = 0;
        else
            datetime = date_lut.makeDateTime(year, month, day, hour, minute, second);
    }
    else
    {
        if (s_pos - s >= 5)
        {
            
            datetime = 0;
            for (const char * digit_pos = s; digit_pos < s_pos; ++digit_pos)
                datetime = datetime * 10 + *digit_pos - '0';
        }
        else
        {
            if constexpr (throw_exception)
                throw ParsingException("Cannot parse datetime", ErrorCodes::CANNOT_PARSE_DATETIME);
            else
                return false;
        }
    }
    return ReturnType(true);
}
template void readDateTimeTextFallback<void>(time_t &, ReadBuffer &, const DateLUTImpl &);
template bool readDateTimeTextFallback<bool>(time_t &, ReadBuffer &, const DateLUTImpl &);
void skipJSONField(ReadBuffer & buf, const StringRef & name_of_field)