```
$ 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.
{
        switch (*buf.position())
        {
            case '+':
            {
                
                if (has_number)
                    goto end;
                
                if (has_sign)
                {
                    if constexpr (throw_exception)
                        throw ParsingException(
                            "Cannot parse number with multiple sign (+/-) characters",
                            ErrorCodes::CANNOT_PARSE_NUMBER);
                    else
                        return ReturnType(false);
                }
                has_sign = true;
                break;
            }
            case '-':
            {
                if (has_number)
                    goto end;
                if (has_sign)
                {
                    if constexpr (throw_exception)
                        throw ParsingException(
                            "Cannot parse number with multiple sign (+/-) characters",