组织结构图SQL查询

Question

I am trying to create a table to hold an org chart using SQL Server but have not been successful so far. I have tried doing sub-selects and self-joins but I can't get the desired output.

This is what the table looks like today, showing who reports to who:

1    2         3
Bob  Jon     Kevin
Bob  Mark    Paul
Bob  Jon     Ian

My desired outcome is to show all resources in one column, and then display the org chart to the right, like this:

Resource    3        2       1
Kevin      Kevin    Jon     Bob
Paul       Paul     Mark    Bob
Ian        Ian      Jon     Bob
Jon        NULL     Jon     Bob
Mark       NULL     Mark    Bob
Bob        NULL     NULL    Bob

I am not sure if this is possible with SQL or what strategies I should use to accomplish it. Pivots, CTEs, etc.

Answer 1

You can use apply to unpivot and then use select distinct to remove duplicates:

select distinct v.*
from t cross apply
     (values (col3, col3, col2, col1),
             (col2, col2, col1, null),
             (col1, col1, null, null)
     ) v(resource, col3, col2, col1);