अभिभावक बच्चा mysql

संपादित करें

गॉर्डन नोट को संबोधित करते हुए काम करने वाला नमूना

क्वेरी नोड पथ की गणना करती है क्योंकि आपने पेड़ की अधिकतम गहराई तय की है, और इसके द्वारा क्रमित करें।

SQL Fiddle

MySQL 5.5.30 स्कीमा सेटअप :

create table mytable(id int, parent_id int, name varchar(100));

insert mytable(id, parent_id, name)
values (1, null, 'Home'),
(2, null, 'Services'),
(3, 2, 'Baking'),
(4, 3, 'Cakes'),
(5, 3, 'Bread'),
(6, 5, 'Flat Bread'),
(7, 1, 'Something');

क्वेरी 1 :

select t0.*,
  concat(
      case coalesce(t4.Parent_ID, 0) 
        when 0 then ''
        else concat(cast(t4.Parent_ID as char), '\\')
      end,
      case coalesce(t3.Parent_ID, 0) 
        when 0 then ''
        else concat(cast(t3.Parent_ID as char), '\\')
      end,
      case coalesce(t2.Parent_ID, 0) 
        when 0 then ''
        else concat(cast(t2.Parent_ID as char), '\\')
      end,
      case coalesce(t1.Parent_ID, 0) 
        when 0 then ''
        else concat(cast(t1.Parent_ID as char), '\\')
      end,
      case coalesce(t0.Parent_ID, 0) 
        when 0 then ''
        else concat(cast(t0.Parent_ID as char), '\\')
      end,
      cast(t0.id as char)
    ) as path
from mytable t0 
    left join mytable t1 on t0.Parent_ID = t1.Id
    left join mytable t2 on t1.Parent_ID = t2.Id
    left join mytable t3 on t2.Parent_ID = t3.Id
    left join mytable t4 on t3.Parent_ID = t4.Id
order by 
  concat(
      case coalesce(t4.Parent_ID, 0) 
        when 0 then ''
        else concat(cast(t4.Parent_ID as char), '\\')
      end,
      case coalesce(t3.Parent_ID, 0) 
        when 0 then ''
        else concat(cast(t3.Parent_ID as char), '\\')
      end,
      case coalesce(t2.Parent_ID, 0) 
        when 0 then ''
        else concat(cast(t2.Parent_ID as char), '\\')
      end,
      case coalesce(t1.Parent_ID, 0) 
        when 0 then ''
        else concat(cast(t1.Parent_ID as char), '\\')
      end,
      case coalesce(t0.Parent_ID, 0) 
        when 0 then ''
        else concat(cast(t0.Parent_ID as char), '\\')
      end,
      cast(t0.id as char)
    )

परिणाम :

| ID | PARENT_ID |       NAME |    PATH |
-----------------------------------------
|  1 |    (null) |       Home |       1 |
|  7 |         1 |  Something |     1\7 |
|  2 |    (null) |   Services |       2 |
|  3 |         2 |     Baking |     2\3 |
|  4 |         3 |      Cakes |   2\3\4 |
|  5 |         3 |      Bread |   2\3\5 |
|  6 |         5 | Flat Bread | 2\3\5\6 |