parent details in same row conditionally - sql

Question

I have a table Called EmployeeLevel
Id Position ShouldApproveLeave
1000 1 0
2000 2 1
3000 3 0
4000 4 0
Note that the bool column ShouldApproveLeave is true for only one row
I have a table Employee with the following structure with LevelId as foreign key to EmployeeLevel
Id ParentId Name LevelId
1000 NULL Jack 1000
2000 1000 John 2000
3000 2000 Nick 3000
4000 3000 James 4000
I need a query to get employee details, position details as well as the manager responsible for his leave approval as below
query (id = 4000)
Id Name LevelPosition LeaveApprovalLevel LeaveApprovingManager
4000 James 4 2 John
query (id = 3000)
Id Name LevelPosition LeaveApprovalLevel LeaveApprovingManager
3000 Nick 3 2 John
query (id = 2000)
Id Name LevelPosition LeaveApprovalLevel LeaveApprovingManager
2000 John 2 2 John
Also I want to check leave approving manager only upwards in the hierarchy.
query (id = 1000)
Id Name LevelPosition LeaveApprovalLevel LeaveApprovingManager
1000 Jack 1 2 NULL
I wrote a CTE to get the manager with LeaveApproving bit set. Getting the employee with level is also straightforward. My issue is to get all these details in the same row.
So the question really is I got individual results for employee details and Leave Approving manager. How can I get this in a single row?
I managed to get individual queries for the following
employee details
Id ParentId Name Position
4000 3000 James 4
LeaveApprovalLevel details
Level
2
LeaveApprovingManager details
Id ParentId Name
2000 1000 John
How can I join these so that I will get this?
Id Name LevelPosition LeaveApprovalLevel LeaveApprovingManager
4000 James 4 2 John
Any tips are appreciated.

Answer 1

Here is one approach:
Get the hierarchy for the employee.
Use joins to get the information on the flag you want.
Use joins to bring back all the information you want.
As a query:
with cte as (
select e.id, e.parentid, 1 as lev
from employee e
where id = 4000
union all
select cte.id, e.parentid, lev + 1
from cte join
employee e
on e.id = cte.parentid
)
select e.*, el.*
from cte join
employee e
on cte.id = e.id join
employee el
on cte.parentid = el.id join
EmployeeLevel eml
on cte.parentid = eml.id;

Answer 2

try this
SELECT e1.Id, e1.Name, el1.Position as LevelPosition, el2.Position as LeaveApprovalLevel, e2.Name as LeaveApprovingManager FROM Employee e1 INNER JOIN EmployeeLevel el1 ON e1.LevelId = el1.Id LEFT JOIN Employee e2 ON e1.ParentId = e2.Id LEFT JOIN EmployeeLevel el2 ON e2.LevelId = el2.Id;
Here is the response
Check, here is the working Fiddle