SQL INSERT with conditional statement IF THEN ELSE - sql-server

Question

I am trying to MERGE values from one table to another. One of the values is a conditional value, but it looks like I am not getting the syntax correctly. Initially, I was using an IF-THEN-ELSE statement but was advise to use a CASE statement instead.
Here is the gist the syntax that is failing:
CREATE PROCEDURE EmployeeMerge
AS
BEGIN
SET NOCOUNT ON;
MERGE INTO Employee AS t1
USING
(SELECT
EmployeeName,
Zip,
UpdateDate
FROM table2) AS t2
ON (t1.EmployeeID = t2.EmployeeID)
WHEN MATCHED AND t2.UpdatedDate > t1.UpdatedDate THEN
UPDATE
SET
t1.EmployeeName = s.EmployeeName,
t1.Zip =
(CASE
WHEN t2.ZipExt IS NULL OR t2.ZipExt = '' THEN t2.Zip
ELSE (t2.Zip + '-' + t2.ZipExt)
END),
t1.UpdatedDate = t2.UpdateDate
WHEN NOT MATCHED THEN
INSERT (EmployeeName,
Zip,
ModDate)
VALUES
(t2.Name,
(CASE
WHEN t2.ZipExt IS NULL OR t2.ZipExt = '' THEN t2.Zip
ELSE (t2.Zip + '-' + t2.Zip_Ext)
END),
t2.UpdatedDate)
OUTPUT
deleted.*,
$action,
inserted.*
END; **-- A MERGE statement must be terminated by a semi-colon (;)**
GO
This MERGE statement works just fine if I do not implement the condition, i.e. simply set the t1.Zip = t2.Zip, but of course, this is avoiding the t2.ZipExt field.

Answer 1

A MERGE statement must be terminated by a semi-colon (;)
You haven't terminated the MERGE with a semicolon. You have terminated BEGIN-END. Move the semicolon.

Answer 2

I never really cared for the merge command. There are times where I can see using it, but for the most part, it's more complicated than I like my SQL.
UPDATE e
SET e.EmployeeName=t1.EmployeeName
, e.Zip=CASE
WHEN t1.ZipExt IS NULL OR t1.ZipExt = '' THEN t1.Zip
ELSE (t1.Zip + '-' + t1.ZipExt)
END
, e.UpdatedDate=t1.UpdatedDate
FROM Employee e
INNER JOIN Table t1 ON e.EmployeeID = t1.EmployeeID
WHERE t1.UpdatedDate > e.UpdatedDate
INSERT INTO Employee (EmployeeName,Zip,UpdatedDate)
SELECT
t1.EmployeeName
, t1.Zip=CASE
WHEN t1.ZipExt IS NULL OR t1.ZipExt = '' THEN t1.Zip
ELSE (t1.Zip + '-' + t1.ZipExt)
END
, t1.UpdatedDate
FROM Table t1
LEFT JOIN Employee e ON e.EmployeeID = t1.EmployeeID
WHERE e.EmployeeID IS NULL