Get Root parent of child in Hierarchical table
问题 I have a table with hierarchical data in it, the structure goes like this: ID ParentId ---- ---------- 1 NULL 2 1 3 2 4 2 5 3 6 5 If I pass the node Id I would like to get the top most node Id/details by traversing through all its parents in SQL. I tried CTE, i somehow cannot get the combination correct. However, i got this working as a function but it is so slow that i had to post this question. In the above example if I pass 6, i would want to have the top most i.e. 1. By traversing through