Method getRequiredColumns

src/Interpreters/TableJoin.cpp:498–507

}

NamesWithAliases TableJoin::getRequiredColumns(const Block & sample, const Names & action_required_columns) const
{
    NameSet required_columns(action_required_columns.begin(), action_required_columns.end());

    for (auto & column : requiredJoinedNames())
        if (!sample.has(column))
            required_columns.insert(column);

    return getNamesWithAliases(required_columns);
}

Block TableJoin::getRequiredRightKeys(const Block & right_table_keys, std::vector<String> & keys_sources) const
{