Method resolveWindow

src/Analyzer/Resolve/QueryAnalyzer.cpp:2800–2924

Resolve window function window node. * * Node can be identifier or window node. * Example: SELECT count(*) OVER w FROM test_table WINDOW w AS (PARTITION BY id); * Example: SELECT count(*) OVER (PARTITION BY id); * * If node has parent window name specified, then parent window definition is searched in nearest query scope WINDOW section. * If node is identifier, than node is replaced

  * Window node frame is validated.
  */
ProjectionName QueryAnalyzer::resolveWindow(QueryTreeNodePtr & node, IdentifierResolveScope & scope)
{
    std::string parent_window_name;
    auto * identifier_node = node->as<IdentifierNode>();

    ProjectionName result_projection_name;
    QueryTreeNodePtr parent_window_node;

    if (identifier_node)
        parent_window_name = identifier_node->getIdentifier().getFullName();
    else if (auto * window_node = node->as<WindowNode>())
        parent_window_name = window_node->getParentWindowName();

    if (!parent_window_name.empty())
    {
        auto * nearest_query_scope = scope.getNearestQueryScope();

        if (!nearest_query_scope)
            throw Exception(ErrorCodes::BAD_ARGUMENTS, "Window '{}' does not exist.", parent_window_name);

        auto & scope_window_name_to_window_node = nearest_query_scope->window_name_to_window_node;

        auto window_node_it = scope_window_name_to_window_node.find(parent_window_name);
        if (window_node_it == scope_window_name_to_window_node.end())
            throw Exception(ErrorCodes::BAD_ARGUMENTS,
                "Window '{}' does not exist. In scope {}",
                parent_window_name,
                nearest_query_scope->scope_node->formatASTForErrorMessage());

        parent_window_node = window_node_it->second;

        auto [_, inserted] = windows_in_resolve_process.emplace(parent_window_node.get());
        if (!inserted)
            throw Exception(ErrorCodes::UNSUPPORTED_METHOD,
                "Recursive window {}. In scope {}",
                node->formatASTForErrorMessage(),
                scope.scope_node->formatASTForErrorMessage());

        if (identifier_node)
        {
            node = parent_window_node->clone();
            node->removeAlias();
            result_projection_name = parent_window_name;
        }
        else
        {
            mergeWindowWithParentWindow(node, parent_window_node, scope);
        }
    }

    auto & window_node = node->as<WindowNode &>();
    window_node.setParentWindowName({});

    ProjectionNames partition_by_projection_names = resolveExpressionNodeList(
        window_node.getPartitionByNode(),
        scope,
        false /*allow_lambda_expression*/,
        false /*allow_table_expression*/);