如何将case when结果应用于SQL 2008查询中的where条件

SELECT name, 
       CASE 
           WHEN salary >= 10000 THEN '高薪' 
           ELSE CAST(salary AS VARCHAR(10)) 
       END AS salary 
FROM employees 
WHERE CASE 
          WHEN salary >= 10000 THEN '高薪' 
          ELSE CAST(salary AS VARCHAR(10)) 
      END >= '5000';

SELECT name, salary 
FROM (
    SELECT name, 
           CASE 
               WHEN salary >= 10000 THEN '高薪' 
               ELSE CAST(salary AS VARCHAR(10)) 
           END AS salary 
    FROM employees
) AS derived_table 
WHERE derived_table.salary >= '5000';