Detect loops in hierarchy using SQL Server query

Asked Dec 21 '12 at 05:09

Active Dec 21 '12 at 06:11

Viewed 89 times

Possible Duplicate:
SQL - detecting loops in parent child relations

I have a simple table with 2 columns id and parentid:

id    |   parentid
------------------
2         1
3         2
4         3
1         4

For example, in the above table, 1 is a child of 1 itself (1->2->3->4->1). How to detect such cases?

Would I require an extra column?

edited May 23 '17 at 12:04

Community

asked Dec 21 '12 at 05:09

mhn

Sounds recursive,, anyone thinking about CTE? – Adeel Ahmed Dec 21 '12 at 05:16
2

This might help: http://stackoverflow.com/a/3230256/1373170 – Pablo Romeo Dec 21 '12 at 05:39

0 Answers0