```
$ 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.
return ReturnType(false);
        UInt8 day = pos[0] - '0';
        if (isNumericASCII(pos[1]))
        {
            day = day * 10 + pos[1] - '0';
            pos += 2;
        }
        else
            pos += 1;
        buf.position() = pos;
        date = LocalDate(year, month, day);
        return ReturnType(true);
    }
    else
        return readDateTextFallback<ReturnType>(date, buf);
}
template <typename ReturnType = void>
inline ReturnType readDateTextImpl(DayNum & date, ReadBuffer & buf)
{
    static constexpr bool throw_exception = std::is_same_v<ReturnType, void>;
    LocalDate local_date;
    if constexpr (throw_exception)
        readDateTextImpl<ReturnType>(local_date, buf);
    else if (!readDateTextImpl<ReturnType>(local_date, buf))
        return false;
    date = DateLUT::instance().makeDayNum(local_date.year(), local_date.month(), local_date.day());
    return ReturnType(true);
}
template <typename ReturnType = void>
inline ReturnType readDateTextImpl(ExtendedDayNum & date, ReadBuffer & buf)