Function queryNodeToSelectQuery

src/Planner/Utils.cpp:175–202

}

ASTPtr queryNodeToSelectQuery(const QueryTreeNodePtr & query_node, bool set_subquery_cte_name)
{
    auto & query_node_typed = query_node->as<QueryNode &>();

    // In case of cross-replication we don't know what database is used for the table.
    // Each shard will use the default database (in the case of cross-replication shards may have different defaults).
    auto result_ast = query_node_typed.toAST({
        .qualify_indentifiers_with_database = false,
        .set_subquery_cte_name = set_subquery_cte_name
    });

    while (true)
    {
        if (auto * /*select_query*/ _ = result_ast->as<ASTSelectQuery>())
            break;
        if (auto * select_with_union = result_ast->as<ASTSelectWithUnionQuery>())
            result_ast = select_with_union->list_of_selects->children.at(0);
        else if (auto * subquery = result_ast->as<ASTSubquery>())
            result_ast = subquery->children.at(0);
        else
            throw Exception(ErrorCodes::LOGICAL_ERROR, "Query node invalid conversion to select query");
    }

    if (result_ast == nullptr)
        throw Exception(ErrorCodes::LOGICAL_ERROR, "Query node invalid conversion to select query");

    return result_ast;
}

namespace
{