Древовидная структура -> HTML

В копилку полезных запросов. Берем дерево команд Исследователя и получаем на выходе HTML код.

EXECUTE BLOCK
  RETURNS(name VARCHAR(200))
AS
  DECLARE VARIABLE prev_indent INTEGER = 0;
  DECLARE VARIABLE indent INTEGER;
  DECLARE VARIABLE I INTEGER;
  DECLARE VARIABLE n VARCHAR(200);
BEGIN
  name = '
';
  SUSPEND;

  FOR
    WITH RECURSIVE
      group_tree AS (
        SELECT id, parent, name,
          CAST('' AS VARCHAR(255)) AS indent
        FROM gd_command
        WHERE parent IS NULL

        UNION ALL

        SELECT g.id, g.parent, g.name,
          h.indent || rpad('', 2)
        FROM gd_command g JOIN group_tree h
          ON g.parent = h.id
          
      )
    SELECT
      CHARACTER_LENGTH(gt.indent),
      TRIM(gt.name)
    FROM
      group_tree gt
    INTO :indent, :n
    DO BEGIN
      I = :indent - :prev_indent;
    
      IF (:I > 0) THEN
      BEGIN
        name = '
';
        SUSPEND;
        prev_indent = :indent;
      END
    
      IF (:I < 0) THEN
      BEGIN
        name = '
';
        SUSPEND;
        prev_indent = :indent;
      END
      
      name = '
' || :n || '
';
      SUSPEND;
    END

  name = '
';
  SUSPEND;
END