If join returns null then join on default row - sql

Question

I am trying to join 2 tables on a row, and if that row is null, then join that row to the default row.
Table 1: Events
EventID EventName
----------- -------------
1 January
2 February
3 March
4 April
Table 2: Menus
MenuID EventID MenuVersion
---------- ----------- ---------------
1 1
2 3 2
3 4 4
4 4
What I have Tried
SELECT * FROM Events
LEFT JOIN Menus
ON Events.EventID = Menus.EventID
Output I'm Getting
EventID EventName MenuID EventID MenuVersion
----------- ------------- --------- ---------- ---------------
1 January
2 February
3 March 2 3 2
4 April 3 4 4
The default row of the Menus table in this case is the row with the highest MenuID and a null EventID.
Output I want
EventID EventName MenuID EventID MenuVersion
----------- ------------- --------- ---------- ---------------
1 January 4 4
2 February 4 4
3 March 2 3 2
4 April 3 4 4

Answer 1

Cross apply the default row and use its values when no row is left joined on.
DECLARE #Events TABLE (EventId INT, EventName VARCHAR(12));
DECLARE #Menus TABLE (MenuId INT, EventId INT, MenuVersion INT);
INSERT INTO #Events (EventId, EventName)
VALUES
(1, 'January'),
(2, 'February'),
(3, 'March'),
(4, 'April');
INSERT INTO #Menus (MenuId, EventId, MenuVersion)
VALUES
(1, null, 1),
(2, 3, 2),
(3, 4, 4),
(4, null, 4);
SELECT E.EventId, E.EventName, COALESCE(M.MenuId, D.MenuId) MenuId, M.EventId, COALESCE(M.MenuVersion, D.MenuVersion) MenuVersion
FROM #Events E
LEFT JOIN #Menus M ON M.EventID = E.EventID
CROSS APPLY (SELECT TOP 1 * FROM #Menus WHERE EventId IS NULL ORDER BY MenuId DESC) D;
Returns as requested:
EventId EventName MenuId EventId MenuVersion
1 January 4 NULL 4
2 February 4 NULL 4
3 March 2 3 2
4 April 3 4 4
Note: If you set out your questions like this in future with the DDL/DML statements you'll get a much faster response because it saves people from having to type it all in.