JOIN two databases

Question

I'm trying to join two tables which seems like it should be simple. However, I'm struggling to find the solution.
I have a table in my order entry database with the following schema:
OrderID, TaskID, HoursBilled
I have another table in my time and attendance system with the following schema:
OrderID, TaskID, HoursCompleted
I want to Join these tables together so I can compare the hours billed for an order by task to the hours completed. However, there are instances when there are hours billed for a task for an order that do not have any hours completed in the time and attendance
system and there are also hours completed for an order in the time and attendance system for tasks that have not been billed on a job. The results I'm looking for are something like this:
OrderID, TaskID, HoursBilled, HoursCompleted
1, 2, 10, NULL
1, 3, NULL, 4
1, 5, 6, 2
1, 4, 5, 9
Currently I'm using LEFT OUTER JOIN on OrderID and TaskID but this excludes the hours completed for tasks that were not billed for the job.
What's the best way to handle this scenario? I could do a separate query and UNION the results, but I'm hoping there's a better solution then that.

Answer 1

I think I solved my own problem as I was writing the sample code. Does this make sense?
If OBJECT_ID('tempdb..#ORDER') is not null Drop Table #ORDER
If OBJECT_ID('tempdb..#TIME') is not null Drop Table #TIME
CREATE TABLE #ORDER
(OrderID int
,TaskID int
,HoursBilled decimal(18,4))
CREATE TABLE #TIME
(OrderID int
,TaskID int
,HoursCompleted decimal(18,4))
INSERT INTO #ORDER
VALUES (1, 2, 10)
INSERT INTO #ORDER
VALUES (1, 5, 6)
INSERT INTO #ORDER
VALUES (1, 4, 5)
INSERT INTO #TIME
VALUES (1, 3, 4)
INSERT INTO #TIME
VALUES (1, 5, 2)
INSERT INTO #TIME
VALUES (1, 4, 9)
SELECT ISNULL(o.OrderID, t.OrderID) AS 'OrderID'
--, t.OrderID
, ISNULL(o.TaskID, t.TaskID) As 'TaskID'
--, t.TaskID
, HoursBilled
, HoursCompleted
FROM #ORDER o
FULL OUTER JOIN #TIME t
ON o.OrderID = t.OrderID
AND o.TaskID = t.TaskID