```
$ 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.
{
        decltype(rng.state_) multiplier, increment, state;
        readText(multiplier, buf);
        assertChar(' ', buf);
        readText(increment, buf);
        assertChar(' ', buf);
        readText(state, buf);
        if (multiplier != rng.multiplier())
            throw Exception(ErrorCodes::INCORRECT_DATA, "Incorrect multiplier in pcg32: expected {}, got {}", rng.multiplier(), multiplier);
        if (increment != rng.increment())
            throw Exception(ErrorCodes::INCORRECT_DATA, "Incorrect increment in pcg32: expected {}, got {}", rng.increment(), increment);
        rng.state_ = state;
    }
};
}