**Use case**

Viewing binary data such as bitmasks, hashes, internal representation of IEEE-754 numbers, etc.
Mostly for debugging.

**Describe the solution you'd like**

Similar to `hex`/`unhex`.

`bin` - returns a string with `0` and `1`. Bits are in "human" order, most significant first. Most significant zero bits are not printed (except the case with single zero).

**Describe alternatives you've considered**

Now I have to run interactive `python` from command line, but I will be more happy using ClickHouse.

**Caveats**

The name `bin` may suggest that the function will "split data into bins" but it is completely unrelated.
{
        const ColumnPtr & column = arguments[0].column;
        if (const ColumnString * col = checkAndGetColumn<ColumnString>(column.get()))
        {
            auto col_res = ColumnUInt8::create();
            ColumnUInt8::Container & vec_res = col_res->getData();
            vec_res.resize(col->size());
            const ColumnString::Chars & vec_src = col->getChars();
            const ColumnString::Offsets & offsets_src = col->getOffsets();
            size_t prev_offset = 0;
            UInt32 result = 0;
            for (size_t i = 0; i < vec_res.size(); ++i)
            {
                vec_res[i] = DB::parseIPv4(reinterpret_cast<const char *>(&vec_src[prev_offset]), reinterpret_cast<unsigned char*>(&result));
                prev_offset = offsets_src[i];
            }
            return col_res;
        }
        else
            throw Exception("Illegal column " + arguments[0].column->getName()
                            + " of argument of function " + getName(),
                            ErrorCodes::ILLEGAL_COLUMN);
    }
};
class FunctionIsIPv6String : public FunctionIPv6StringToNum