Function buildQueryToReadColumnsFromTableExpression

src/Analyzer/Utils.cpp:1073–1101

}

QueryTreeNodePtr buildQueryToReadColumnsFromTableExpression(const NamesAndTypes & columns,
    const QueryTreeNodePtr & table_expression,
    ContextMutablePtr & context)
{
    auto projection_columns = columns;

    QueryTreeNodes subquery_projection_nodes;
    subquery_projection_nodes.reserve(projection_columns.size());

    for (const auto & column : projection_columns)
        subquery_projection_nodes.push_back(std::make_shared<ColumnNode>(column, table_expression));

    if (subquery_projection_nodes.empty())
    {
        auto constant_data_type = std::make_shared<DataTypeUInt64>();
        subquery_projection_nodes.push_back(std::make_shared<ConstantNode>(1UL, constant_data_type));
        projection_columns.push_back({"1", std::move(constant_data_type)});
    }

    updateContextForSubqueryExecution(context);

    auto query_node = std::make_shared<QueryNode>(std::move(context));

    query_node->getProjection().getNodes() = std::move(subquery_projection_nodes);
    query_node->resolveProjectionColumns(projection_columns);
    query_node->getJoinTree() = table_expression;

    return query_node;
}

QueryTreeNodePtr buildSubqueryToReadColumnsFromTableExpression(const NamesAndTypes & columns,
    const QueryTreeNodePtr & table_expression,