```
$ 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.
{
    return readUUIDTextImpl<void>(uuid, buf);
}
inline bool tryReadUUIDText(UUID & uuid, ReadBuffer & buf)
{
    return readUUIDTextImpl<bool>(uuid, buf);
}
template <typename T>
inline T parse(const char * data, size_t size);
template <typename T>
inline T parseFromString(const std::string_view & str)
{
    return parse<T>(str.data(), str.size());
}
template <typename ReturnType = void>
ReturnType readDateTimeTextFallback(time_t & datetime, ReadBuffer & buf, const DateLUTImpl & date_lut);
/** In YYYY-MM-DD hh:mm:ss or YYYY-MM-DD format, according to specified time zone.
  * As an exception, also supported parsing of unix timestamp in form of decimal number.
  */
template <typename ReturnType = void>
inline ReturnType readDateTimeTextImpl(time_t & datetime, ReadBuffer & buf, const DateLUTImpl & date_lut)