https://clickhouse-test-reports.s3.yandex.net/8367/333ec2e496f4fe4addd22d5fa7c5c2a499099c57/fuzzer/fuzzer.log#fail1
ExternalQueryBuilder::composeLoadKeysQuery(const Columns & key_columns, const std::vector<size_t> & requested_rows, LoadKeysMethod method, size_t partition_key_prefix)
{
    if (!dict_struct.key)
        throw Exception{"Composite key required for method", ErrorCodes::UNSUPPORTED_METHOD};
    WriteBufferFromOwnString out;
    writeString("SELECT ", out);
    auto first = true;
    for (const auto & key_or_attribute : boost::join(*dict_struct.key, dict_struct.attributes))
    {
        if (!first)
            writeString(", ", out);
        first = false;
        if (!key_or_attribute.expression.empty())
        {
            writeParenthesisedString(key_or_attribute.expression, out);
            writeString(" AS ", out);
        }
        writeQuoted(key_or_attribute.name, out);
    }
    writeString(" FROM ", out);
    if (!db.empty())
    {