```
$ 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())
        throw Exception("Unexpected EOF for key '" + name_of_field.toString() + "'", ErrorCodes::INCORRECT_DATA);
    else if (*buf.position() == '"') 
    {
        NullOutput sink;
        readJSONStringInto(sink, buf);
    }
    else if (isNumericASCII(*buf.position()) || *buf.position() == '-' || *buf.position() == '+' || *buf.position() == '.') 
    {
        if (*buf.position() == '+')
            ++buf.position();
        double v;
        if (!tryReadFloatText(v, buf))
            throw Exception("Expected a number field for key '" + name_of_field.toString() + "'", ErrorCodes::INCORRECT_DATA);
    }
    else if (*buf.position() == 'n') 
    {
        assertString("null", buf);
    }
    else if (*buf.position() == 't') 
    {
        assertString("true", buf);
    }
    else if (*buf.position() == 'f') 
    {
        assertString("false", buf);
    }
    else if (*buf.position() == '[')
    {