c# - linq to sql recursive query

Question

EmployeeId  Name  ManagerId
------------------------------
1           A     null
2           B     null
3           C     1
4           D     3
5           E     2

just using this table, how can a linq query (using linq to sql) be written to fetch the parent data recursively.

For instance if the Employer Id selected is 4 it should give list of employees with Id: 4, 3, 1

Thanks.

Answer 1

This .AsHierarchy() extension method may be useful: link. However, this only works by providing an easy way to throw your results into linked objects. In order to do that, it'll just get all the records and run its own local recursive query.

If you're looking for a LINQ query that will directly translate to a recursive SQL query via LINQ to SQL, you won't find it. For the best performance, a CTE in a stored procedure is probably what you're looking for. If you have a really simple page that needs to load the whole tree anyway, the AsHierarchy method would probably fit your needs.