How to self JOIN recursively in SQL?
I just enhance the work of Thomas. If you need to get the depth of the hierarchy and getting the parentid here is the code.
This was almost the same with Thomas' work.
With Family As
(
Select s.ID, s.ParentSeriesId, 0 as Depth
From Series s
Where ID = @ParentID <--- this was removed if you intend to get all hierarchy of the record. You can retain this if you want
Union All
Select s2.ID, s2.ParentSeriesId < --- change to **Family.ParentID**, Depth + 1
From Series s2
Join Family
On Family.ID = s2.ParentSeriesId
)
Select *
From Family
That's all. I know it's too late but I hope anyone who encounter this may help them. Thanks Thomas for the original code. :)
If you are using SQL Server 2005+, you can use common-table expressions
With Family As
(
Select s.ID, s.ParentSeriesId, 0 as Depth
From Series s
Where ID = @ParentID
Union All
Select s2.ID, s2.ParentSeriesId, Depth + 1
From Series s2
Join Family
On Family.ID = s2.ParentSeriesId
)
Select *
From Family
For more:
Recursive Queries Using Common Table Expressions