Function executeSubQueryWithOneRow

src/Interpreters/executeSubQuery.cpp:89–131

}

Block executeSubQueryWithOneRow(const String & query, ContextMutablePtr query_context, bool internal, bool tolerate_multi_rows)
{
    modifyQueryContext(query_context, internal);

    Block block;
    std::exception_ptr exception;
    auto thread = ThreadFromGlobalPool([query_context = std::move(query_context), &query, internal, tolerate_multi_rows, &block, &exception]() {
        try
        {
            CurrentThread::QueryScope query_scope{query_context};
            {
                auto block_io = executeQuery(query, query_context, internal);

                auto input_stream = block_io.getInputStream();
                input_stream->readPrefix();
                block = input_stream->read();

                if (!tolerate_multi_rows && block.rows() != 1)
                    throw Exception(ErrorCodes::TOO_MANY_ROWS, "Unexcepted block");

                while (const auto & tmp_block = input_stream->read())
                {
                    if (tmp_block.rows() > 0)
                        throw Exception(ErrorCodes::TOO_MANY_ROWS, "Unexcepted block");
                }

                input_stream->readSuffix();

                block_io.onFinish();
            }
        }
        catch (...)
        {
            exception = constructException(query_context);
        }
    });
    thread.join();

    if (exception)
        std::rethrow_exception(exception);

    return block;
}

void executeSubQuery(const String & query, ContextMutablePtr query_context, std::function<void(Block &)> proc_block, bool internal)
{