self referencing table with child table

Question

I have a self-referencing table with content like this:

Self-referencing parent table
ID  ParentID    Name
---------------------
1               John
2   1           Mike
3   2           Erin
4   1           Janie
5               Eric
6   5           Peter

The tree hierarchy should look like this

• John
  • Mike
    • Erin
  • Janie
• Eric
  • Peter

And a child table that stores the leaf of parent table that looks like this:

ID  Sales
3   100
3   100
4   200
4   200
6   300
6   300
6   300

I'm trying to roll-up the sum from the leaf node up to the hierarchy so it would return as ..

ID  Name    Sum
1   John    800
2   Mike    200
3   Erin    200
4   Janie   400
5   Eric    900
6   Peter   900

Any ideas how to achieve this in sql 2008? Thanks in advance.

Answer 1

EDIT All aggregation moved out of the CTE

WITH
  tree AS
(
  SELECT
    id                AS root_id,
    name              AS root_name,
    id                AS leaf_id
  FROM
    yourTreeTable

  UNION ALL

  SELECT
    tree.root_id      AS root_id,
    tree.name         AS root_name,
    yourTreeTable.id  AS leaf_id
  FROM
    tree
  INNER JOIN
    yourTreeTable
      ON tree.leaf_id = yourTreeTable.ParentID
)
SELECT
  tree.root_id,
  tree.root_name,
  COALESCE(SUM(yourScoresTable.score), 0) AS total
FROM
  tree
LEFT JOIN
  yourScoresTable
    ON yourScoresTable.ID = tree.leafID
GROUP BY
  tree.root_id,
  tree.root_name

Answer 2

Here it is:

Let's supose this schema:

​create table #parent (
ID int,
ParentID int,
Name varchar(50) );

create table #child (
ID int,
Sales int );

The query is self explained:

WITH 
  tree AS
(
  SELECT
    id as id_parent,
    id as id
  FROM
    #parent
  UNION ALL
  SELECT
    tree.id_parent as id_parent,
    #parent.id AS id
  FROM
    tree
  INNER JOIN
    #parent    
      ON tree.id = #parent.ParentID
)
SELECT
  #parent.id,
  #parent.name,
  COALESCE(SUM(#child.Sales), 0) AS total
FROM
  #parent
LEFT JOIN
  tree
    ON #parent.ID = tree.id_parent
LEFT JOIN
  #child on tree.id = #child.id
GROUP BY
  #parent.id,
  #parent.name

CTE returns a list of 'leafs' for each employee (#parent), then query sums all sales for this 'leafs'. You can test it running.

EDITED

Query is fixed.