```
$ 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.
{
    if (buf.eof() || *buf.position() != quote)
    {
        throw ParsingException(ErrorCodes::CANNOT_PARSE_QUOTED_STRING,
            "Cannot parse quoted string: expected opening quote '{}', got '{}'",
            std::string{quote}, buf.eof() ? "EOF" : std::string{*buf.position()});
    }
    ++buf.position();
    while (!buf.eof())
    {
        char * next_pos = find_first_symbols<'\\', quote>(buf.position(), buf.buffer().end());
        appendToStringOrVector(s, buf, next_pos);
        buf.position() = next_pos;
        if (!buf.hasPendingData())
            continue;
        if (*buf.position() == quote)
        {
            ++buf.position();
            if (enable_sql_style_quoting && !buf.eof() && *buf.position() == quote)
            {
                s.push_back(quote);
                ++buf.position();
                continue;