Parent-Child Ragged hierarchy

Question

Hi
I have a parent child ragged hisrarchy. I want to build level wise dimension to be able to report using crystal .
The PC table I have is like
Child     Parent
A11      A1
A12      A1
A111    A11
A112    A11
A113    A11
A121    A12
A122    A12
A1121  A112
A1221  A122
A1222  A122
I want to solve this as a level based hierarchy using universe like:
LEV1 LEV2 LEV3 LEV4
A1 A12 A122 A1222
A1 A12 A122 A1221
A1 A11 A112 A1121
A1 A12 A122
A1 A12 A121
A1 A11 A113
A1 A11 A112
A1 A11 A111
A1 A12
A1 A11
Can somebody please put some light on this how can I achieve this?
Thanks
Atul

Answer 1

Hi Atul,
You can use a Derived Table that flatten the hierarchy.
Here is a sample based on the example you provided, you just have to replace "child", "parent" and "myTable" strings by the corrseponding column and table names:
SELECT DISTINCT
     Z.child,
     A.parent_1,
     A.child_1,
     A.parent_2,
     A.child_2,
     A.parent_3,
     A.child_3,
     Z.parent AS parent_4,
     Z.child AS child_4
FROM myTable Z,
     SELECT DISTINCT
          A.parent_1,
          A.child_1,
          A.parent_2,
          A.child_2,
          Z.parent AS parent_3,
          Z.child AS child_3
     FROM myTable Z,
          SELECT DISTINCT
               A.parent_1,
               A.child_1,
               Z.parent AS parent_2,
               Z.child AS child_2
          FROM myTable Z,
               SELECT DISTINCT
                    parent AS parent_1,
                    child AS child_1
                FROM myTable
                WHERE parent = 0 OR parent IS NULL
          ) A
          WHERE A.child_1 = Z.parent
     ) A
     WHERE A.child_2 = Z.parent
) A
WHERE A.child_3 = Z.parent
UNION
SELECT DISTINCT
     A.child_3 AS child,
     A.parent_1,
     A.child_1,
     A.parent_2,
     A.child_2,
     A.parent_3,
     A.child_3,
     NULL AS parent_4,
     NULL AS child_4
FROM myTable Z,
     SELECT DISTINCT
          A.parent_1,
          A.child_1,
          A.parent_2,
          A.child_2,
          Z.parent AS parent_3,
          Z.child AS child_3
     FROM myTable Z,
          SELECT DISTINCT
               A.parent_1,
               A.child_1,
               Z.parent AS parent_2,
               Z.child AS child_2
          FROM myTable Z,
               SELECT DISTINCT
                    parent AS parent_1,
                    child AS child_1
                FROM myTable
                WHERE parent = 0 OR parent IS NULL
          ) A
          WHERE A.child_1 = Z.parent
     ) A
     WHERE A.child_2 = Z.parent
) A
WHERE A.child_3 NOT IN (SELECT parent FROM myTable)
UNION
SELECT DISTINCT
     A.child_2 AS child,
     A.parent_1,
     A.child_1,
     A.parent_2,
     A.child_2,
     NULL AS parent_3,
     NULL AS child_3,
     NULL AS parent_4,
     NULL AS child_4
FROM myTable Z,
     SELECT DISTINCT
          A.parent_1,
          A.child_1,
          Z.parent AS parent_2,
          Z.child AS child_2
     FROM myTable Z,
          SELECT DISTINCT
               parent AS parent_1,
               child AS child_1
           FROM myTable
           WHERE parent = 0 OR parent IS NULL
     ) A
     WHERE A.child_1 = Z.parent
) A
WHERE A.child_2 NOT IN (SELECT parent FROM myTable)
UNION
SELECT DISTINCT
     A.child_1 AS child,
     A.parent_1,
     A.child_1,
     NULL AS parent_2,
     NULL AS child_2,
     NULL AS parent_3,
     NULL AS child_3,
     NULL AS parent_4,
     NULL AS child_4
FROM myTable Z,
     SELECT DISTINCT
          parent AS parent_1,
          child AS child_1
      FROM myTable
      WHERE parent = 0 OR parent IS NULL
) A
WHERE A.child_1 NOT IN (SELECT parent FROM myTable)
Regards,
Didier