請參閱 : REPLICATE (Transact-SQL)
B. 使用 REPLICATE 和 DATALENGTH

CREATE TABLE Table1 (
   id int
 , TableYear NVARCHAR(4)
 , TableMonth NVARCHAR(4)
);

INSERT INTO Table1 values
(1, '2022', N'1'),
(2, '2022', N'2'),
(3, '2022', N'3'),
(4, '2022', N'10'),
(5, '2022', N'11');

SELECT id,TableYear+RIGHT('00'+TableMonth,2) AS YYYYMM
FROM Table1

https://dbfiddle.uk/?rdbms=sqlserver_2017&fiddle=921a4185d280f9f3f11bb6b9cdfb75a8

補充REPLICATE作法

CREATE TABLE Table1 (
   id int
 , TableYear VARCHAR(4)
 , TableMonth VARCHAR(4)
);

INSERT INTO Table1 values
(1, '2022', N'1'),
(2, '2022', N'2'),
(3, '2022', N'3'),
(4, '2022', N'10'),
(5, '2022', N'11');

SELECT id,TableYear+REPLICATE('0',2-DATALENGTH(TableMonth))+TableMonth AS YYYYMM
FROM Table1

https://dbfiddle.uk/?rdbms=sqlserver_2017&fiddle=89f002b052465592f3202361efc92b53

select * into #A from (values
 ('1','2022','1')
,('2','2022','2')
,('3','2022','3')
,('4','2022','10')
,('5','2022','11')
) as A([id],[TableYear],[TableMonth]);

select [id],  [TableYear]*100+[TableMonth] [YYYYMM]
from #A;