```
$ 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() + 10 <= buf.buffer().end())
    {
        char * pos = buf.position();
        
        
        
        
        
        UInt16 year = (pos[0] - '0') * 1000 + (pos[1] - '0') * 100 + (pos[2] - '0') * 10 + (pos[3] - '0');
        pos += 5;
        if (isNumericASCII(pos[-1]))
            return ReturnType(false);
        UInt8 month = pos[0] - '0';
        if (isNumericASCII(pos[1]))
        {
            month = month * 10 + pos[1] - '0';
            pos += 3;
        }
        else
            pos += 2;
        if (isNumericASCII(pos[-1]))