SQL语句 = “ WITH RECURSIVE tree AS (” + “ SELECT id, parent_id, 0 AS depth” + “ FROM 类目” + “ WHERE parent_id IS NULL” + “ UNION ALL” + “ SELECT c.id, c.parent_id, t.depth + 1” + “ FROM 类目 c” + “ INNER JOIN tree t ON c.parent_id = t.id” + “ )” + “ SELECT * FROM tree”
记录集.置SQL语句 (SQL语句, 数据库)