希望这只是一个演示示例，而不是您真正的表结构.

Hopefully this is just a demo example not your real table structure.

SELECT Employee,
       Manager,
       CASE
         WHEN EXISTS(SELECT *
                     FROM   Employee e2
                     WHERE  e2.Manager = e1.Employee) THEN 1
         ELSE 0
       END As IsAManager
FROM   Employee e1  

有关 SQL Server 如何处理 CASE 表达式中的 EXISTS 子查询的详细信息，请参阅 这篇文章.

For details of how SQL Server processes EXISTS Subqueries in CASE Expressions see this article.