Microsoft SQL Server: Error with Group By

I'm new to Microsoft SQL Server 2014. I run this SQL code:

SELECT TOP(10) 'DBSG' as seek_entity, * 
FROM DBSG..PM00200

and get this result:

Next, I want to find out total line items for that entity with code below.

WITH vw_pm00200_all AS
(
    SELECT TOP(10) 
        'DBSG' as seek_entity, *    
    FROM 
        DBSG..PM00200
)
SELECT
    seek_entity,
    COUNT(*) AS total
FROM
    vw_pm00200_all
GROUP BY
    1

Sadly, I get this error. I have no idea why it failed.

Msg 164, Level 15, State 1, Line 9
Each GROUP BY expression must contain at least one column that is not an outer reference.

Lastly, please advise is Microsoft SQL Server based on Transact-SQL?

Copyright Notice：Content Author:「Ong K.S」，Reproduced under the CC 4.0 BY-SA copyright license with a link to the original source and this disclaimer.
Link to original article：https://stackoverflow.com/questions/74738157/microsoft-sql-server-error-with-group-by