```
$ 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 readJSONStringInto<Vector, bool>(s, buf);
}
template <typename Vector>
void readStringUntilWhitespaceInto(Vector & s, ReadBuffer & buf);
struct NullOutput
{
    void append(const char *, size_t) {}
    void push_back(char) {}
};
void parseUUID(const UInt8 * src36, UInt8 * dst16);
void parseUUIDWithoutSeparator(const UInt8 * src36, UInt8 * dst16);
void parseUUID(const UInt8 * src36, std::reverse_iterator<UInt8 *> dst16);
void parseUUIDWithoutSeparator(const UInt8 * src36, std::reverse_iterator<UInt8 *> dst16);
template <typename ReturnType>
ReturnType readDateTextFallback(LocalDate & date, ReadBuffer & buf);
template <typename ReturnType = void>
inline ReturnType readDateTextImpl(LocalDate & date, ReadBuffer & buf)