```
$ 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.
{
    readQuoted(x, buf);
}
inline void skipWhitespaceIfAny(ReadBuffer & buf, bool one_line = false)
{
    if (!one_line)
        while (!buf.eof() && isWhitespaceASCII(*buf.position()))
            ++buf.position();
    else
        while (!buf.eof() && isWhitespaceASCIIOneLine(*buf.position()))
            ++buf.position();
}
void skipJSONField(ReadBuffer & buf, const StringRef & name_of_field);
/** Read serialized exception.
  * During serialization/deserialization some information is lost
  * (type is cut to base class, 'message' replaced by 'displayText', and stack trace is appended to 'message')
  * Some additional message could be appended to exception (example: you could add information about from where it was received).
  */
Exception readException(ReadBuffer & buf, const String & additional_message = "", bool remote_exception = false);
void readAndThrowException(ReadBuffer & buf, const String & additional_message = "");
/** Helper function for implementation.
  */
template <ReadIntTextCheckOverflow check_overflow = ReadIntTextCheckOverflow::CHECK_OVERFLOW, typename T>
static inline const char * tryReadIntText(T & x, const char * pos, const char * end)