你需要对外部查询进行排序。

对子查询进行排序是不允许的，因为它是没有意义的，请考虑这个简单的例子。

WITH CTE AS
(    SELECT  ID
     FROM (VALUES (1), (2)) AS t (ID)
     ORDER BY ID DESC
 SELECT *
FROM CTE
 ORDER BY ID ASC;
外层查询的排序已经覆盖了内层查询的排序，使其成为一种浪费。
这不仅仅是对外层查询进行明确的排序，在更复杂的情况下，SQL Server可以以任何方式对子查询进行排序，以实现合并连接或分组等。因此，保证顺序或结果的唯一方法是按照你的意愿对外部查询进行排序。
由于你可能在外部查询中没有你需要的所有数据，你可能需要在CTE中再创建一个列来用于排序。
WITH ctedivisiondesc AS
    SELECT *
FROM    (   SELECT  DH1.ID_NUM,
                        DH1.DIV_CDE,
                        DDF.DEGREE_DESC AS DivisionDesc,
                        DTE_DEGR_CONFERRED,
                        ROW_NUMBER() OVER (PARTITION BY ID_NUM ORDER BY DTE_DEGR_CONFERRED DESC) AS [ROW NUMBER],
WHEN DDF.DEGREE_DESC = 'Certificate' THEN 1
WHEN DDF.DEGREE_DESC = 'Undegraduate' THEN 2
WHEN DDF.DEGREE_DESC = 'Graduate' THEN 3
WHEN DDF.DEGREE_DESC = 'Doctor of Chiropractic' THEN 4
ELSE 5
END AS SortOrder
                FROM    TmsePrd.dbo.DEGREE_HISTORY AS DH1
                        INNER JOIN TmsePrd.dbo.DEGREE_DEFINITION AS DDF
                            ON DH1.DEGR_CDE = DDF.DEGREE
            ) AS t
    WHERE   t.[ROW NUMBER] <= 1
SELECT  ID_NUM,
        DIV_CDE,