SQL to change data type to timestamp not working

Hello,

I am using an ODBC mongodb PowerBI connector to connect and filter my data. I am using the following query:

SELECT *
FROM [03.MyTable]
WHERE [Activities] LIKE '%1234-0001%';

-- Modify the data type of the Timestamp column
ALTER TABLE [03.MyTable]
ALTER COLUMN [Timestamp] TIMESTAMP;

I am able to return only values where Activities contains 1234-0001, however, the data type for the "Timestamp" column is still showing as Text instead of TIMESTAMP. I know i can change this later in PowerBI, but I'd like to do this with the SQL.

Any help would be appreciated. Thanks in advance!